Acids and Bases
An Introduction
by Anthony Carpi, Ph.D.
For thousands of years people have known that vinegar, lemon juice and many other foods taste sour. However, it was not until a few hundred years ago that it was discovered why these things taste sour - because they are all acids. The term acid, in fact, comes from the Latin term acere, which means "sour". While there are many slightly different definitions of acids and bases, in this lesson we will introduce the fundamentals of acid/base chemistry.
In the seventeenth century, the Irish writer and amateur chemist Robert Boyle first labeled substances as either acids or bases (he called bases alkalies) according to the following characteristics:
* Acids taste sour, are corrosive to metals, change litmus (a dye extracted from lichens) red, and become less acidic when mixed with bases.
* Bases feel slippery, change litmus blue, and become less basic when mixed with acids.
While Boyle and others tried to explain why acids and bases behave the way they do, the first reasonable definition of acids and bases would not be proposed until 200 years later.
In the late 1800s, the Swedish scientist Svante Arrhenius proposed that water can dissolve many compounds by separating them into their individual ions. Arrhenius suggested that acids are compounds that contain hydrogen and can dissolve in water to release hydrogen ions into solution. For example, hydrochloric acid (HCl) dissolves in water as follows:
HCl H2O
H+(aq) + Cl-(aq)
Arrhenius defined bases as substances that dissolve in water to release hydroxide ions (OH-) into solution. For example, a typical base according to the Arrhenius definition is sodium hydroxide (NaOH):
NaOH H2O
Na+(aq) + OH-(aq)
The Arrhenius definition of acids and bases explains a number of things. Arrhenius's theory explains why all acids have similar properties to each other (and, conversely, why all bases are similar): because all acids release H+ into solution (and all bases release OH-). The Arrhenius definition also explains Boyle's observation that acids and bases counteract each other. This idea, that a base can make an acid weaker, and vice versa, is called neutralization.
Neutralization: As you can see from the equations, acids release H+ into solution and bases release OH-. If we were to mix an acid and base together, the H+ ion would combine with the OH- ion to make the molecule H2O, or plain water:
H+(aq) + OH-(aq) H2O
The neutralization reaction of an acid with a base will always produce water and a salt, as shown below:
Acid Base Water Salt
HCl + NaOH H2O + NaCl
HBr + KOH H2O + KBr
Though Arrhenius helped explain the fundamentals of acid/base chemistry, unfortunately his theories have limits. For example, the Arrhenius definition does not explain why some substances, such as common baking soda (NaHCO3), can act like a base even though they do not contain hydroxide ions.
In 1923, the Danish scientist Johannes Brønsted and the Englishman Thomas Lowry published independent yet similar papers that refined Arrhenius' theory. In Brønsted's words, "... acids and bases are substances that are capable of splitting off or taking up hydrogen ions, respectively." The Brønsted-Lowry definition broadened the Arrhenius concept of acids and bases.
The Brønsted-Lowry definition of acids is very similar to the Arrhenius definition, any substance that can donate a hydrogen ion is an acid (under the Brønsted definition, acids are often referred to as proton donors because an H+ ion, hydrogen minus its electron, is simply a proton).
The Brønsted definition of bases is, however, quite different from the Arrhenius definition. The Brønsted base is defined as any substance that can accept a hydrogen ion. In essence, a base is the opposite of an acid. NaOH and KOH, as we saw above, would still be considered bases because they can accept an H+ from an acid to form water. However, the Brønsted-Lowry definition also explains why substances that do not contain OH- can act like bases. Baking soda (NaHCO3), for example, acts like a base by accepting a hydrogen ion from an acid as illustrated below:
Acid Base Salt
HCl + NaHCO3 H2CO3 + NaCl
In this example, the carbonic acid formed (H2CO3) undergoes rapid decomposition to water and gaseous carbon dioxide, and so the solution bubbles as CO2 gas is released.
pH
Under the Brønsted-Lowry definition, both acids and bases are related to the concentration of hydrogen ions present. Acids increase the concentration of hydrogen ions, while bases decrease the concentration of hydrogen ions (by accepting them). The acidity or basicity of something, therefore, can be measured by its hydrogen ion concentration.
In 1909, the Danish biochemist Sören Sörensen invented the pH scale for measuring acidity. The pH scale is described by the formula:
pH = -log [H+] Note: concentration is commonly abbreviated by using square brackets, thus [H+] = hydrogen ion concentration. When measuring pH, [H+] is in units of moles of H+ per liter of solution.
For example, a solution with [H+] = 1 x 10-7 moles/liter has a pH equal to 7 (a simpler way to think about pH is that it equals the exponent on the H+ concentration, ignoring the minus sign). The pH scale ranges from 0 to 14. Substances with a pH between 0 and less than 7 are acids (pH and [H+] are inversely related - lower pH means higher [H+]). Substances with a pH greater than 7 and up to 14 are bases (higher pH means lower [H+]). Right in the middle, at pH = 7, are neutral substances, for example, pure water. The relationship between [H+] and pH is shown in the table below alongside some common examples of acids and bases in everyday life.
[H+] pH Example
Acids 1 X 100 0 HCl
1 x 10-1 1 Stomach acid
1 x 10-2 2 Lemon juice
1 x 10-3 3 Vinegar
1 x 10-4 4 Soda
1 x 10-5 5 Rainwater
1 x 10-6 6 Milk
Neutral 1 x 10-7 7 Pure water
Bases 1 x 10-8 8 Egg whites
1 x 10-9 9 Baking soda
1 x 10-10 10 Tums® antacid
1 x 10-11 11 Ammonia
1 x 10-12 12 Mineral lime - Ca(OH)2
1 x 10-13 13 Drano®
1 x 10-14 14 NaOH
Reference:http://www.visionlearning.com/library/module_viewer.php?mid=58
Saturday, July 10, 2010
Friday, June 18, 2010
Objectives:
1. Trace the history of zoology through making a concept map
2. Develop understanding in the beginning of zoology
History.
The study of zoology can be viewed as a series of efforts to analyze and classify animals. Attempts at classification as early as 400 BC are known from documents in the Hippocratic Collection. Aristotle, however, was the first to devise a system of classifying animals that recognized a basic unity of plan among diverse organisms; he arranged groups of animals according to mode of reproduction and habitat. Observing the development of such animals as the dogfish, chick, and octopus, he noted that general structures appear before specialized ones, and he also distinguished between asexual and sexual reproduction. His Historia Animalium contains accurate descriptions of extant animals of Greece and Asia Minor. He was also interested in form and structure and concluded that different animals can have similar embryological origins and that different structures can have similar functions.
In Roman times Pliny the Elder (WHOSE PHOTO IS AT THE SIDE) compiled four volumes on zoology in his 37-volume treatise called Historia Naturalis. Although widely read during the Middle Ages, they are little more than a collection of folklore, myth, and superstition. One of the more influential figures in the history of physiology, the Greek physician Galen, dissected farm animals, monkeys, and other mammals and described many features accurately, although some were wrongly applied to the human body. His misconceptions, especially with regard to the movement of blood, remained virtually unchanged for hundreds of years. In the 17th century, the English physician William Harvey established the true mechanism of blood circulation.
Until the Middle Ages, zoology was a conglomeration of folklore, superstition, misconception, and descriptions of animals, but during the 12th century it began to emerge as a science. Perhaps the most important naturalist of the era was the German scholar St. Albertus Magnus, who denied many of the superstitions associated with biology and reintroduced the work of Aristotle. The anatomical studies of Leonardo da Vinci were far in advance of the age. His dissections and comparisons of the structure of humans and other animals led him to important conclusions. He noted, for example, that the arrangement of joints and bones in the leg are similar in both horses and humans, thus grasping the concept of homology (the similarity of corresponding parts in different kinds of animals, suggesting a common grouping). The value of his work in anatomy was not recognized in his time. Instead, the Belgian physician Andreas Vesalius is considered the father of anatomy; he circulated his writings and established the principles of comparative anatomy. See ANATOMY
Classification dominated zoology throughout most of the 17th and 18th centuries. The Swedish botanist Carolus Linnaeus developed a system of nomenclature that is still used today—the binomial system of genus and species —and established taxonomy as a discipline. He followed the work of the English naturalist John Ray in relying upon the form of teeth and toes to differentiate mammals and upon beak shape to classify birds. Another leading systematist of this era was the French biologist Comte Georges Leclerc de Buffon. The study of comparative anatomy was extended by such men as Georges Cuvier, who devised a systematic organization of animals based on specimens sent to him from all over the world.Although the word cell was introduced in the 17th century by the English scientist Robert Hooke, it was not until 1839 that two Germans, Matthias Schleiden and Theodor Schwann, proved that the cell is the common structural unit of living things. The cell concept provided impetus for progress in embryology, founded by the Russian scientist Karl von Baer, and for the development by a Frenchman, Claude Bernard, of the study of animal physiology, including the concept of homeostasis (the stability of the body’s internal environment). See CELL,; PHYSIOLOGY,.The organization of scientific expeditions in the 18th and 19th centuries gave trained observers the opportunity to study plant and animal life throughout the world. The most famous expedition was the voyage of the Beagle in the early 1830s. During this voyage, Charles Darwin observed the plant and animal life of South America and Australia and developed his theory of evolution by natural selection. Although Darwin recognized the importance of heredity in understanding the evolutionary process, he was unaware of the work of a contemporary, the Austrian monk Gregor Mendel, who first formulated the concept of particulate hereditary factors—later called genes. Mendel’s work remained obscure
Activity:
trace the history of zoology by making a concept map.
Reference: http://www.history.com/encyclopedia.do?articleId=226469
1. Trace the history of zoology through making a concept map
2. Develop understanding in the beginning of zoology
History.
The study of zoology can be viewed as a series of efforts to analyze and classify animals. Attempts at classification as early as 400 BC are known from documents in the Hippocratic Collection. Aristotle, however, was the first to devise a system of classifying animals that recognized a basic unity of plan among diverse organisms; he arranged groups of animals according to mode of reproduction and habitat. Observing the development of such animals as the dogfish, chick, and octopus, he noted that general structures appear before specialized ones, and he also distinguished between asexual and sexual reproduction. His Historia Animalium contains accurate descriptions of extant animals of Greece and Asia Minor. He was also interested in form and structure and concluded that different animals can have similar embryological origins and that different structures can have similar functions.
In Roman times Pliny the Elder (WHOSE PHOTO IS AT THE SIDE) compiled four volumes on zoology in his 37-volume treatise called Historia Naturalis. Although widely read during the Middle Ages, they are little more than a collection of folklore, myth, and superstition. One of the more influential figures in the history of physiology, the Greek physician Galen, dissected farm animals, monkeys, and other mammals and described many features accurately, although some were wrongly applied to the human body. His misconceptions, especially with regard to the movement of blood, remained virtually unchanged for hundreds of years. In the 17th century, the English physician William Harvey established the true mechanism of blood circulation.
Until the Middle Ages, zoology was a conglomeration of folklore, superstition, misconception, and descriptions of animals, but during the 12th century it began to emerge as a science. Perhaps the most important naturalist of the era was the German scholar St. Albertus Magnus, who denied many of the superstitions associated with biology and reintroduced the work of Aristotle. The anatomical studies of Leonardo da Vinci were far in advance of the age. His dissections and comparisons of the structure of humans and other animals led him to important conclusions. He noted, for example, that the arrangement of joints and bones in the leg are similar in both horses and humans, thus grasping the concept of homology (the similarity of corresponding parts in different kinds of animals, suggesting a common grouping). The value of his work in anatomy was not recognized in his time. Instead, the Belgian physician Andreas Vesalius is considered the father of anatomy; he circulated his writings and established the principles of comparative anatomy. See ANATOMY
Classification dominated zoology throughout most of the 17th and 18th centuries. The Swedish botanist Carolus Linnaeus developed a system of nomenclature that is still used today—the binomial system of genus and species —and established taxonomy as a discipline. He followed the work of the English naturalist John Ray in relying upon the form of teeth and toes to differentiate mammals and upon beak shape to classify birds. Another leading systematist of this era was the French biologist Comte Georges Leclerc de Buffon. The study of comparative anatomy was extended by such men as Georges Cuvier, who devised a systematic organization of animals based on specimens sent to him from all over the world.Although the word cell was introduced in the 17th century by the English scientist Robert Hooke, it was not until 1839 that two Germans, Matthias Schleiden and Theodor Schwann, proved that the cell is the common structural unit of living things. The cell concept provided impetus for progress in embryology, founded by the Russian scientist Karl von Baer, and for the development by a Frenchman, Claude Bernard, of the study of animal physiology, including the concept of homeostasis (the stability of the body’s internal environment). See CELL,; PHYSIOLOGY,.The organization of scientific expeditions in the 18th and 19th centuries gave trained observers the opportunity to study plant and animal life throughout the world. The most famous expedition was the voyage of the Beagle in the early 1830s. During this voyage, Charles Darwin observed the plant and animal life of South America and Australia and developed his theory of evolution by natural selection. Although Darwin recognized the importance of heredity in understanding the evolutionary process, he was unaware of the work of a contemporary, the Austrian monk Gregor Mendel, who first formulated the concept of particulate hereditary factors—later called genes. Mendel’s work remained obscure
Activity:
trace the history of zoology by making a concept map.
Reference: http://www.history.com/encyclopedia.do?articleId=226469
Saturday, March 13, 2010
Digestive system
Lesson Plan in Biology
Title of Episode: The Digestive System and its Event
Name of Episode: Let us see how, and we will sing how….
General Objective
Understand the Anatomy and Physiology of Humans
Specific Objectives
At the end of 60-minute period, at least 85% of the students will be able to:
a. describe the structures and its functions in the digestive system through;
1.1 video presentations.
1.2 small group discussions
1.3 crossword puzzle
b. develop thorough understanding on how digestive system works and its importance.
c. trace the events involved in digestion and the structures and its functions in the digestive system through;
3.1 composing a song and present it in class.
3.2 labeling using the answer sheets
Materials Needed
For the students:
• Reference book
• Writing materials
For the Teacher:
• Computer
• CD/DVD
For the Activity:
• Activity Sheet
Resources:
Bailey D, B., et al., Concepts in Biology 12th Edition, Mc-Graw Hill, International Edition
Seeley R,R., et al., Essentials of Anatomy and Physiology 6th Edition, Mc-Graw Hill, International Edition
Audesirk T., et al., Biology: Life on Earth 7th Edition, Prentice Hall.
Instructor Resource center on CD-ROM
Your Digestive System and How It Works http://digestive.niddk.nih.gov/ddiseases/pubs/yrdd/
Topic: Digestion and digestive System
Introduction
system The digestive system is made up of the digestive tract—a series of hollow organs joined in a long, twisting tube from the mouth to the anus—and other organs that help the body break down and absorb food (see figure).
Organs that make up the digestive tract are the mouth, esophagus, stomach, small intestine, large intestine—also called the colon—rectum, and anus. Inside these hollow organs is a lining called the mucosa. In the mouth, stomach, and small intestine, the mucosa contains tiny glands that produce juices to help digest food. The digestive tract also contains a layer of smooth muscle that helps break down food and move it along the tract.
Two “solid” digestive organs, the liver and the pancreas, produce digestive juices that reach the intestine through small tubes called ducts. The gallbladder stores the liver’s digestive juices until they are needed in the intestine. Parts of the nervous and circulatory systems also play major roles in the digestive.
Learning Tasks/ Learning Experiences
Activity
The students will view different video presentations regarding digestive system. After viewing the video presentations, they will then proceed to their respective group to have a small group discussion using the questions given to them. This will only be 5 minutes
After, doing the small group discussion, the information officer of the group will be called to give their opinion regarding the issues and concerns given to them through the guide questions. This will only be 3-5 minutes.
A group may compose of:
Madam Chair/ Young Master: serves as the leader and the lead discussant of the group.
Secretary: The one that will record the flow of the discussion.
Media man: The one that will deliver the information on what has been discussed.
The students will compose a song regarding the events of digestion and the structures and its functions of the digestive system. They will be presenting it in the class. Each group will be given 5-8 minutes to prepare their composition and 2 minutes presentation.
Analysis
There will be questions that will be given to the students before and after the video presentations, these questions will serve as their guide as they go along the way with their small group discussion.
Questions that will be given before viewing the video presentations
1. What are the structures and its functions involved in digestion?
2. What types of digestion that takes place in the mouth?
3. What are enzymes used to digest:
3.1 carbohydrates,
3.2 fats,
3.3 proteins?
4. Where does the digestion of;
4.1 carbohydrates
4.2 fats
4.3 proteins take place?
Question for the group
In one word, how could you describe digestive system in terms of; structures, functions in general and its importance?
Abstraction
For the students to really retain what are those insights that were given by the different group, the teacher will reiterate and condense all the ideas given by each group.
Application
In order to determine whether the students had able to attain the given objectives, the students will present their newly composed songs regarding the events in digestion and the structures involved.
There will also be sets of questionnaires and activity sheets that will be distributed to each of the group and each of the students.
Home Activity
The students will visit the blog created, Animal World. There are series of activities related to digestive system that are recently posted.
Title of Episode: The Digestive System and its Event
Name of Episode: Let us see how, and we will sing how….
General Objective
Understand the Anatomy and Physiology of Humans
Specific Objectives
At the end of 60-minute period, at least 85% of the students will be able to:
a. describe the structures and its functions in the digestive system through;
1.1 video presentations.
1.2 small group discussions
1.3 crossword puzzle
b. develop thorough understanding on how digestive system works and its importance.
c. trace the events involved in digestion and the structures and its functions in the digestive system through;
3.1 composing a song and present it in class.
3.2 labeling using the answer sheets
Materials Needed
For the students:
• Reference book
• Writing materials
For the Teacher:
• Computer
• CD/DVD
For the Activity:
• Activity Sheet
Resources:
Bailey D, B., et al., Concepts in Biology 12th Edition, Mc-Graw Hill, International Edition
Seeley R,R., et al., Essentials of Anatomy and Physiology 6th Edition, Mc-Graw Hill, International Edition
Audesirk T., et al., Biology: Life on Earth 7th Edition, Prentice Hall.
Instructor Resource center on CD-ROM
Your Digestive System and How It Works http://digestive.niddk.nih.gov/ddiseases/pubs/yrdd/
Topic: Digestion and digestive System
Introduction
system The digestive system is made up of the digestive tract—a series of hollow organs joined in a long, twisting tube from the mouth to the anus—and other organs that help the body break down and absorb food (see figure).
Organs that make up the digestive tract are the mouth, esophagus, stomach, small intestine, large intestine—also called the colon—rectum, and anus. Inside these hollow organs is a lining called the mucosa. In the mouth, stomach, and small intestine, the mucosa contains tiny glands that produce juices to help digest food. The digestive tract also contains a layer of smooth muscle that helps break down food and move it along the tract.
Two “solid” digestive organs, the liver and the pancreas, produce digestive juices that reach the intestine through small tubes called ducts. The gallbladder stores the liver’s digestive juices until they are needed in the intestine. Parts of the nervous and circulatory systems also play major roles in the digestive.
Learning Tasks/ Learning Experiences
Activity
The students will view different video presentations regarding digestive system. After viewing the video presentations, they will then proceed to their respective group to have a small group discussion using the questions given to them. This will only be 5 minutes
After, doing the small group discussion, the information officer of the group will be called to give their opinion regarding the issues and concerns given to them through the guide questions. This will only be 3-5 minutes.
A group may compose of:
Madam Chair/ Young Master: serves as the leader and the lead discussant of the group.
Secretary: The one that will record the flow of the discussion.
Media man: The one that will deliver the information on what has been discussed.
The students will compose a song regarding the events of digestion and the structures and its functions of the digestive system. They will be presenting it in the class. Each group will be given 5-8 minutes to prepare their composition and 2 minutes presentation.
Analysis
There will be questions that will be given to the students before and after the video presentations, these questions will serve as their guide as they go along the way with their small group discussion.
Questions that will be given before viewing the video presentations
1. What are the structures and its functions involved in digestion?
2. What types of digestion that takes place in the mouth?
3. What are enzymes used to digest:
3.1 carbohydrates,
3.2 fats,
3.3 proteins?
4. Where does the digestion of;
4.1 carbohydrates
4.2 fats
4.3 proteins take place?
Question for the group
In one word, how could you describe digestive system in terms of; structures, functions in general and its importance?
Abstraction
For the students to really retain what are those insights that were given by the different group, the teacher will reiterate and condense all the ideas given by each group.
Application
In order to determine whether the students had able to attain the given objectives, the students will present their newly composed songs regarding the events in digestion and the structures involved.
There will also be sets of questionnaires and activity sheets that will be distributed to each of the group and each of the students.
Home Activity
The students will visit the blog created, Animal World. There are series of activities related to digestive system that are recently posted.
Saturday, January 2, 2010
Friday, November 20, 2009
Monday, November 9, 2009
Brain Structures and their Functions
The nervous system is your body's decision and communication center. The central nervous system (CNS) is made of the brain and the spinal cord and the peripheral nervous system (PNS) is made of nerves. Together they control every part of your daily life, from breathing and blinking to helping you memorize facts for a test. Nerves reach from your brain to your face, ears, eyes, nose, and spinal cord... and from the spinal cord to the rest of your body. Sensory nerves gather information from the environment, send that info to the spinal cord, which then speed the message to the brain. The brain then makes sense of that message and fires off a response. Motor neurons deliver the instructions from the brain to the rest of your body. The spinal cord, made of a bundle of nerves running up and down the spine, is similar to a superhighway, speeding messages to and from the brain at every second.
The brain is made of three main parts: the forebrain, midbrain, and hindbrain. The forebrain consists of the cerebrum, thalamus, and hypothalamus (part of the limbic system). The midbrain consists of the tectum and tegmentum. The hindbrain is made of the cerebellum, pons and medulla. Often the midbrain, pons, and medulla are referred to together as the brainstem.
The Cerebrum:The cerebrum or cortex is the largest part of the human brain, associated with higher brain function such as thought and action. The cerebral cortex is divided into four sections, called "lobes": the frontal lobe, parietal lobe, occipital lobe, and temporal lobe. Here is a visual representation of the cortex:
What do each of these lobes do?
• Frontal Lobe- associated with reasoning, planning, parts of speech, movement, emotions, and problem solving
• Parietal Lobe- associated with movement, orientation, recognition, perception of stimuli
• Occipital Lobe- associated with visual processing
• Temporal Lobe- associated with perception and recognition of auditory stimuli, memory, and speech
Note that the cerebral cortex is highly wrinkled. Essentially this makes the brain more efficient, because it can increase the surface area of the brain and the amount of neurons within it. We will discuss the relevance of the degree of cortical folding (or gyrencephalization) later.
A deep furrow divides the cerebrum into two halves, known as the left and right hemispheres. The two hemispheres look mostly symmetrical yet it has been shown that each side functions slightly different than the other. Sometimes the right hemisphere is associated with creativity and the left hemispheres is associated with logic abilities. The corpus callosum is a bundle of axons which connects these two hemispheres.
Nerve cells make up the gray surface of the cerebrum which is a little thicker than your thumb. White nerve fibers underneath carry signals between the nerve cells and other parts of the brain and body.
The neocortex occupies the bulk of the cerebrum. This is a six-layered structure of the cerebral cortex which is only found in mammals. It is thought that the neocortex is a recently evolved structure, and is associated with "higher" information processing by more fully evolved animals (such as humans, primates, dolphins, etc). For more information about the neocortex, click here.
The Cerebellum: The cerebellum, or "little brain", is similar to the cerebrum in that it has two hemispheres and has a highly folded surface or cortex. This structure is associated with regulation and coordination of movement, posture, and balance.
The cerebellum is assumed to be much older than the cerebrum, evolutionarily. What do I mean by this? In other words, animals which scientists assume to have evolved prior to humans, for example reptiles, do have developed cerebellums. However, reptiles do not have neocortex. Go here for more discussion of the neocortex or go to the following web site for a more detailed look at evolution of brain structures and intelligence: "Ask the Experts": Evolution and Intelligence
Limbic System: The limbic system, often referred to as the "emotional brain", is found buried within the cerebrum. Like the cerebellum, evolutionarily the structure is rather old.
This system contains the thalamus, hypothalamus, amygdala, and hippocampus. Here is a visual representation of this system, from a midsagittal view of the human brain:
Thalamus
Thalamus- a large mass of gray matter deeply situated in the forebrain at the topmost portion of the diencephalon. The structure has sensory and motor functions. Almost all sensory information enters this structure where neurons send that information to the overlying cortex. Axons from every sensory system (except olfaction) synapse here as the last relay site before the information reaches the cerebral cortex.
Hypothalamus
Hypothalamus- part of the diencephalon, ventral to the thalamus. The structure is involved in functions including homeostasis, emotion, thirst, hunger, circadian rhythms, and control of the autonomic nervous system. In addition, it controls the pituitary.
a coronal view
Amygdala
Amygdala- part of the telencephalon, located in the temporal lobe; involved in memory, emotion, and fear. The amygdala is both large and just beneath the surface of the front, medial part of the temporal lobe where it causes the bulge on the surface called the uncus. This is a component of the limbic system.
Hippocampus
Hippocampus- the portion of the cerebral hemisphers in basal medial part of the temporal lobe. This part of the brain is important for learning and memory . . . for converting short term memory to more permanent memory, and for recalling spatial relationships in the world about us
Brain Stem: Underneath the limbic system is the brain stem. This structure is responsible for basic vital life functions such as breathing, heartbeat, and blood pressure. Scientists say that this is the "simplest" part of human brains because animals' entire brains, such as reptiles (who appear early on the evolutionary scale) resemble our brain stem. The brain stem is made of the midbrain, pons, and medulla. Click on the words to learn what these structures do:
Midbrain/Mesencephalon
Midbrain/ Mesencephalon- the rostral part of the brain stem, which includes the tectum and tegmentum. It is involved in functions such as vision, hearing, eyemovement, and body movement. The anterior part has the cerebral peduncle, which is a huge bundle of axons traveling from the cerebral cortex through the brain stem and these fibers (along with other structures) are important for voluntary motor function.
Pons
Pons- part of the metencephalon in the hindbrain. It is involved in motor control and sensory analysis... for example, information from the ear first enters the brain in the pons. It has parts that are important for the level of consciousness and for sleep. Some structures within the pons are linked to the cerebellum, thus are involved in movement and posture.
Medulla
Medulla Oblongata- this structure is the caudal-most part of the brain stem, between the pons and spinal cord. It is responsible for maintaining vital body functions, such as breathing and heartrate
note: There will be illustrations to be given in class
Reference: http://serendip.brynmawr.edu/bb/kinser/Structure1.html
The brain is made of three main parts: the forebrain, midbrain, and hindbrain. The forebrain consists of the cerebrum, thalamus, and hypothalamus (part of the limbic system). The midbrain consists of the tectum and tegmentum. The hindbrain is made of the cerebellum, pons and medulla. Often the midbrain, pons, and medulla are referred to together as the brainstem.
The Cerebrum:The cerebrum or cortex is the largest part of the human brain, associated with higher brain function such as thought and action. The cerebral cortex is divided into four sections, called "lobes": the frontal lobe, parietal lobe, occipital lobe, and temporal lobe. Here is a visual representation of the cortex:
What do each of these lobes do?
• Frontal Lobe- associated with reasoning, planning, parts of speech, movement, emotions, and problem solving
• Parietal Lobe- associated with movement, orientation, recognition, perception of stimuli
• Occipital Lobe- associated with visual processing
• Temporal Lobe- associated with perception and recognition of auditory stimuli, memory, and speech
Note that the cerebral cortex is highly wrinkled. Essentially this makes the brain more efficient, because it can increase the surface area of the brain and the amount of neurons within it. We will discuss the relevance of the degree of cortical folding (or gyrencephalization) later.
A deep furrow divides the cerebrum into two halves, known as the left and right hemispheres. The two hemispheres look mostly symmetrical yet it has been shown that each side functions slightly different than the other. Sometimes the right hemisphere is associated with creativity and the left hemispheres is associated with logic abilities. The corpus callosum is a bundle of axons which connects these two hemispheres.
Nerve cells make up the gray surface of the cerebrum which is a little thicker than your thumb. White nerve fibers underneath carry signals between the nerve cells and other parts of the brain and body.
The neocortex occupies the bulk of the cerebrum. This is a six-layered structure of the cerebral cortex which is only found in mammals. It is thought that the neocortex is a recently evolved structure, and is associated with "higher" information processing by more fully evolved animals (such as humans, primates, dolphins, etc). For more information about the neocortex, click here.
The Cerebellum: The cerebellum, or "little brain", is similar to the cerebrum in that it has two hemispheres and has a highly folded surface or cortex. This structure is associated with regulation and coordination of movement, posture, and balance.
The cerebellum is assumed to be much older than the cerebrum, evolutionarily. What do I mean by this? In other words, animals which scientists assume to have evolved prior to humans, for example reptiles, do have developed cerebellums. However, reptiles do not have neocortex. Go here for more discussion of the neocortex or go to the following web site for a more detailed look at evolution of brain structures and intelligence: "Ask the Experts": Evolution and Intelligence
Limbic System: The limbic system, often referred to as the "emotional brain", is found buried within the cerebrum. Like the cerebellum, evolutionarily the structure is rather old.
This system contains the thalamus, hypothalamus, amygdala, and hippocampus. Here is a visual representation of this system, from a midsagittal view of the human brain:
Thalamus
Thalamus- a large mass of gray matter deeply situated in the forebrain at the topmost portion of the diencephalon. The structure has sensory and motor functions. Almost all sensory information enters this structure where neurons send that information to the overlying cortex. Axons from every sensory system (except olfaction) synapse here as the last relay site before the information reaches the cerebral cortex.
Hypothalamus
Hypothalamus- part of the diencephalon, ventral to the thalamus. The structure is involved in functions including homeostasis, emotion, thirst, hunger, circadian rhythms, and control of the autonomic nervous system. In addition, it controls the pituitary.
a coronal view
Amygdala
Amygdala- part of the telencephalon, located in the temporal lobe; involved in memory, emotion, and fear. The amygdala is both large and just beneath the surface of the front, medial part of the temporal lobe where it causes the bulge on the surface called the uncus. This is a component of the limbic system.
Hippocampus
Hippocampus- the portion of the cerebral hemisphers in basal medial part of the temporal lobe. This part of the brain is important for learning and memory . . . for converting short term memory to more permanent memory, and for recalling spatial relationships in the world about us
Brain Stem: Underneath the limbic system is the brain stem. This structure is responsible for basic vital life functions such as breathing, heartbeat, and blood pressure. Scientists say that this is the "simplest" part of human brains because animals' entire brains, such as reptiles (who appear early on the evolutionary scale) resemble our brain stem. The brain stem is made of the midbrain, pons, and medulla. Click on the words to learn what these structures do:
Midbrain/Mesencephalon
Midbrain/ Mesencephalon- the rostral part of the brain stem, which includes the tectum and tegmentum. It is involved in functions such as vision, hearing, eyemovement, and body movement. The anterior part has the cerebral peduncle, which is a huge bundle of axons traveling from the cerebral cortex through the brain stem and these fibers (along with other structures) are important for voluntary motor function.
Pons
Pons- part of the metencephalon in the hindbrain. It is involved in motor control and sensory analysis... for example, information from the ear first enters the brain in the pons. It has parts that are important for the level of consciousness and for sleep. Some structures within the pons are linked to the cerebellum, thus are involved in movement and posture.
Medulla
Medulla Oblongata- this structure is the caudal-most part of the brain stem, between the pons and spinal cord. It is responsible for maintaining vital body functions, such as breathing and heartrate
note: There will be illustrations to be given in class
Reference: http://serendip.brynmawr.edu/bb/kinser/Structure1.html
Subscribe to:
Posts (Atom)