ch2 the biology of mind

6. Describe the structure of a neuron and explain the path a neural signal takes from a sending neuron to a receiving neuron.

A Neuron consists of a cell body and an axon. The cell body, or soma, contains the nucleus and is surrounded by branching dendrites, the receivers of neurotransmitters. The axon is surrounded by the myelin sheath, a protective sausage-like fatty covering. The ends of the axon branch out in axon terminals. The neurons send electrical signals to each other called action potentials. When the action potential reaches the end of an axon, the neuron releases neurotransmitters. These neurotransmitters move across the synapse (or synaptic gap) into the receptor sites on the receiving neurons dendrites. With the reception of the neurotransmitters, the receiving neuron then starts firing impulses that will signal the action potential to move down its axon. The receiving neuron then starts this process again with another neuron.

13. Explain the effect of acetylcholine on human behavior. Give an example of a problem associated with acetylcholine levels.

Acetylcholine (ACh) plays an important role in learning and memory. It stimulates muscles to contract, including the heart and stomach. It also acts as the messenger between motor neurons and skeletal muscles. If the ACh levels decrease (due to a deterioration in ACh-producing neurons) this may cause Alzheimer's Disease.

9. Explain the role of an agonist and give an example.

Agonists have similar structure to certain neurotransmitter molecules.. Because of this, agonists can mimic its effects on the receiving neuron. Morphine is an example of an agonist. it is similar enough to endorphin, a naturally produced opiate, that it can fit on the neurotransmitter receptors. This excites the Nervous system and creates a temporary "high".

10. Explain the role of an antagonist and give an example.

Antagonists stop an neurotransmitter's function by blocking the receptor sites for neurotransmitters. An example of this is curare. Curare blocks acetylcholine (ACh) receptors involved in muscle movement, causing paralysis.

12. Explain how dopamine affects human behavior. Give an example of a problem associated with dopamine levels.

Dopamine affects the pleasure center of the brain. It is involved in movement, emotions, attention, and learning, as well as cognition, pleasure, and motivation. For an example, food and sex release dopamine into the brain, which is why we seek food and sex. However, low levels of dopamine can lead to Parkinson's disease, and people with dopamine deficiency are also prone to addiction. Too much dopamine can lead to schizophrenia.

15. Explain the effect of endorphins on human behavior. Give an example of how drugs affect endorphin levels.

Endorphins are natural neurotransmitters linked to the pain and pleasure control in the body. They act like opiates, and relieve pain while increasing good feelings in the body. In taking artificial endorphin in drugs, the body may stop producing natural endorphins, causing extreme lows when not taking the drug. It'll lead to depression.

30. Demonstrate how the nervous system and the endocrine system would respond if you found yourself in an emergency situation.

In an emergency, the sympathetic nervous system would respond by arousing and mobilizing the body energy. This would cause the adrenal glands to secrete adrenaline, dilating the eyes, increasing heartbeat (norepinephrine), and activating the fight-or-flight response. The person would become more energized from the actions of the sympathetic nervous system a physically and mentally find a solution, while the endocrine system's release of adrenaline would help the body's functions compensate for the stress.

14. Explain the effect of norepinephrine on human behavior.

Norepinephrine is primarily responsible for physical arousal, learning and memory. It helps control alertness, and it is released by adrenal glands as our body responds to stress in the "fight or flight" response. It directly increase one's heart rate and glucose in the blood for a surge of energy.

32. Explain what it means to be split-brain.Tell something someone with split brain can do better than someone without and something he/she would do worse.

People undergo split brain surgery as a way of alleviating epileptic seizures. Split brained means the corpus callosum connecting the two hemispheres is severed to some degree. They can do different things with each hand better, they are worse at hearing/seeing and understanding with only one ear/eye.

4. Identify and discuss the functions of the Sympathetic Nervous System.

The Sympathetic Nervous System is a division of the Autonomic Nervous System, which is the part of the Peripheral Nervous System that controls the glands and muscles of the internal organs. the Sympathetic Nervous System arouses and mobilizes energy during stressful situations.

8. Explain how a reflex works.

Reflexes are simple automatic responses to a sensory stimulus, such as the knee-jerk response. The spinal reflex pathway generally involves a single sensory neuron and a single motor neuron, with an interneuron in between. Other reflexes, like the pain reflex, travel through a different pathway. If you touch something hot, the pain caused will travel through the sensory neuron to the spinal cord, where an interneuron will issue the command to "pull away or suffer the consequences" order, activating the motor neurons to move your hand away. This response does not require the brain the order the action. Often times, the area in pain will be out of harms way before the brain can even receive, register, and respond to the information that causes you to feel pain.

11. Explain serotonin's impact on human behavior. How do Prozac-type chemicals affect serotonin levels?

Serotonin in the body controls mood, gauges hunger, sleep, and arousal. Too little serotonin in the body may lead to depression. Prozac type chemicals can act as antagonists and block the receptor sites for serotonin, causing the serotonin to circulate in the system longer, giving it more time to exert its effect and regulate the mood.

1. Identify and discuss the functions of the Central Nervous System.

The Central Nervous System (CNS) is made up of the brain and the spinal cord and a complex network of neurons. It is the processing center of the Nervous System. It receives information from the Peripheral Nervous System. The brain is responsible for processing and interpreting sensory information that comes from the spinal cord, and send information back to the spinal cord, which in turn, send it to the rest of the body.

5. Identify and discuss the functions of the Parasympathetic Nervous System.

The Parasympathetic Nervous System is a branch of the Autonomic Nervous system that conserves energy by calming the body. It is the opposite of the Sympathetic Nervous System.

2. Identify and discuss the functions of the Peripheral Nervous System (PNS).

The Peripheral Nervous System (PNS) contains the sensory and motor neurons which connect the body with the Central Nervous System. It includes the Somatic Nervous System, which controls the body's skeletal muscles, and the Autonomic Nervous system, which controls the glands and muscles of internal organs.

3. Identify and discuss the functions of the Somatic Nervous System.

The Somatic Nervous System is a part of the division of the Peripheral Nervous System. It is responsible for the voluntary control of the body movements via skeletal muscles.

7. Define afferent neurons, efferent neurons and interneurons and explain their functions.

The afferent neurons are sensory neurons that receive sensory information from the body to the CNS. They travel to the brain. The efferent neurons are mainly the motor neurons that send information from the brain and the spinal cord to the body. They are going out of the brain, bringing orders to work the muscles. The interneurons are relay neurons that transmit signals from the sensory neurons to the motor neurons. It is mainly located in the brain and spinal cord.

26. Locate an association area and explain their function.

The association areas of the cerebral cortex are the areas not involved in primary motor of sensory functions. They are involved in more advanced mental functions like learning, remembering, thinking, and speaking.. Association areas are found in all four lobes. In the frontal lobes, it enable judgement, planning, and processing information. In the parietal lobes it enable mathematical and spatial reasoning. In the temporal lobes, parts enable us to recognize faces.

28. What is the endocrine system? Identify at least two glands and explain their function.

The body's major endocrine gland is the pituitary gland, which is stimulated by and located under the hypothalamus. It regulates growth and controls the other endocrine glands. The adrenal glands, which are located above the kidneys, secrete arousing hormones, such as adrenaline and norepinephrine, during times of stress. The thyroid (throat) glands affect metabolism, and the pancreas, which is near the kidneys, regulates blood sugar.

33. What is brain plasticity? When does it happen the most and when does it happen the least?

The brain's ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience. It happens the most in children and the least in old age.

21.Locate and explain the function of the brain stem. How does the medulla differ from the pons in function?

The brainstem is located right above the place where the spinal cord swells into the skull. It is the oldest part of the brain and the most vital for survival. It is responsible for automatic survival functions. The medulla, which is the base part of the brainstem, controls heartbeat and breathing. The pons, on the other hand, play a role in coordinating movements.

16.Locate and explain the function of the brainstem, including the medulla, the pons and the reticular formation.

The brainstem is the oldest part of the brain, located where the spinal cord swells into the skull. The brainstem's many parts generally control automatic functions for survival. The medulla, which is the base of the brainstem, controls the heartbeat and breathing. The pons, which lie just above the medulla, control coordinate movements. Inside the brainstem, right between the ears, is the reticular formation. It is a nerve network which connects the spinal cord to the brain and controls arousal.

20. Locate and explain the function of the cerebellum. How does its function differ from the hippocampus?

The cerebellum is located in the back of the brain under the cerebral cortex, at the rear of the brainstem. The cerebellum is responsible for coordinating voluntary movement output and balance. It also helps us judge time, modulate our emotions, and discern different sounds and textures. The hippocampus, on the other hand, is mainly responsible for the formation of memories, and is not involved in movement.

17.Locate the cerebral cortex. Explain its structure and function. What role do glial cells play in the cerebral cortex?

The cerebral cortex is the outer shell of the cerebrum, which is divided into four lobes (parietal, frontal, temporal, and occipital) per hemisphere by fissures, and acts as the brain's main information processing site. It consists of billions of nerve cells, and these nerve cells are supported by glial cells, which support, nourish and protect these neurons. Glial cells nourish neurons with nutrients, and can also help with signal and communication through chatting.

29. Explain the link between the nervous system and the endocrine system. Explain the difference.

The endocrine system and the nervous system are both communications systems in the body, and their form of communications, hormones and neurotransmitters, are chemically similar, some even identical. However, the endocrine system is a much slower form of communication that uses chemical messengers in the form of hormones that travel through the bloodstream. The nervous system, on the other hand, is a much faster electrochemical information-communicating system. The signals and information are transmitted through neurons in the body using neurotransmitters.

27. Identify the right and left hemispheres of the brain, explain how they differ and how they communicate.

The left and right hemispheres of the brain are the left and right sides of the brain, respectively. Contrary to their names, the right hemisphere of the brain controls the left side of the body, and the left controls the right side of the body. The two parts of the brain communicate through a part called the corpus callosum, which is a large band of neural fibers that connect the two hemispheres and carry messages between the two.

23. Locate and explain the function of the limbic system. What parts are included?

The limbic system is a neural system that includes the hippocampus, amygdala, and the hypothalamus. It is located below the cerebral hemispheres. The limbic system is associated with emotions and drives. The amygdala is linked to emotions, particularly aggression and fear.. It is controlled by the pituitary glands. The hippocampus is the part that is associated with processing new memories.The hypothalamus is located below the thalamus, and is responsible for maintenance activities like eating, drinking, and body temperature. It also controls emotions.

24. Locate the motor cortex and explain its function. Why do the fingers and mouth take up the greatest amount of cortical space?

The motor cortex is located at the back of the frontal lobes. It controls specific, voluntary movements of the body. Cortical space is determined by the precision required of a body part. The fingers and mouth are simply used the most, therefore the require more cortical space. Other body parts, such as the arms, may take up more physical space, but require less precision, and therefore smaller in the motor cortex

18. Locate the parietal lobes and explain their function. Locate the occipital lobes and explain their function.

The parietal lobes are the portion of the cerebral cortex lying at the top of the head toward the rear. It receives sensory input for touch and body position. It plays a major part in touch, pressure and temperature. The occipital lobes are located at the back of the head, just above the cerebellum. This lobe is responsible for sight. The primary visual cortex, which receives information from the retinas, is located here.

25. Locate the sensory cortex and explain its function. Why do the lips take up a greater space than other body parts?

The sensory cortex is an area at the front of the parietal lobes. This area of the cerebral cortex registers and processes body touch and movement sensations. The lips take up greater space than other body parts in the sensory cortex area because they are more sensitive than other body regions, and require more nerves devoted to that body part.

34. Where is speech function located in the brain? How does this differ in people that are left handed?

The speech function is located in the left part of the brain (frontal lobe). For left handed people, speech is generally located in the right part of the brain. This is not always true though.

19. Locate the temporal lobes and explain their function. Locate the frontal lobes and explain their function.

The temporal lobes are located above the ears. They include auditory areas, each receiving information primarily from the opposite ear. It is the home to the primary auditory cortex. It is also involved in speech perception. The frontal lobes lie just behind the forehead. They are in charge of integrating speaking and muscle movement. They contain the primary motor cortex. Frontal lobes can also integrate memories and enable judgement, planning, and thought processing.

22. Locate and explain the function of the thalamus. Why is it sometimes called "the grand central station of the brain"?

The thalamus lies on top of the brainstem. It acts as the sensory hub of the brain, directing messages received from various senses and filing them to the appropriate sensory-receiving areas in the cortex. It also transmits replies from the cortex to the cerebellum and the medulla earning it the title of "the grand central station of the brain" because it acts as a train station, sending information to different parts of the brain.

31.Identify the four main kinds of brain scans. Which are for showing structure, and which are for showing function?

fMRI scan shows function, as does PET scan. MRI shows structure, and so does CT.