Nervous System

Question 1

What is the function of the cerebrum?

Answer 1

-The surface of the cerebrum is called the cerebral cortex.
-Specific areas of the cerebral cortex have specific functions.
-Motor areas- Send nerve impulses to skeletal muscles (voluntary) causing them to contract.
-Sensory areas- Receive and interpret nerve impulses from various sensory organs.
-Association areas- Responsible for ‘higher order’ mental activities such as learning, problem solving, speech, and memory.

Question 2

Why do humans have higher order mental capabilities?

Answer 2

-This is because the cerebrum is large and has folds, therefore humans have a large amount of cerebral cortex and are capable of higher order mental capabilities.

Question 3

What is the function of the thalamus?

Answer 3

-It is the relay station for the cerebrum. Furthermore, it receives nerve impulses from other parts of the body and relays them to appropriate locations in the cerebral cortex where they are interpreted.
-It is also responsible for the accommodation response. The thalamus acts as a filter, which all sensory nerves go through for the higher brain. Once the higher brain is aware of the stimulus, the thalamus will filter out if it is not significant the higher brain.

Question 4

What is the function of the medulla oblongata?

Answer 4

-The medulla oblongata function as the cardiovascular center- controls strength of and rate of the heart beat, respiratory center- controls the lungs and breathing rate, controls other autonomic functions- vasoconstriction of blood vessels, digestion (perastalsis), and reflex centrex controls swallowing, coughing, sneezing, and vomiting.

Question 5

What is the function of the hypothalamus?

Answer 5

-It helps maintain homeostasis by regulating sleep, thirst, hunger, body temperature, water balance, and blood pressure.
-It also controls the pituitary which in turn controls the body’s endocrine gland.

Question 6

What is the function of the corpus callosum?

Answer 6

-It allows nerve impulses to be transmitted between the two cerebral hemispheres.

Question 7

What is the function of the cerebellum?

Answer 7

-The functions include maintaining balance, muscle tone, and muscle coordination.
-It receives muscle commands from the cerebrum and ensures that all related muscles contract in the correct sequence.
-It is also involved in learning and remembering motor responses.

Question 8

What is the function of the pons?

Answer 8

-The pons contains a bundle of axons that provides connections between the cerebellum and the rest of the central nervous system.
-The pons also assists the medulla oblongata in controlling breathing rate.

Question 9

What do the nervous and endocrine system do together?

Answer 9

-Work together to regulate and integrate the body systems.
-The neuroendocrine link, which allows the integration of both systems.

Question 10

How does pituitary control the hypothalamus?

Answer 10

-The pituitary is attached to the hypothalamus by the pituitary stalk. This link allows control of the pituitary by the hypothalamus.

Question 11

What is the pituitary gland? What does it consist of, what are their functions?

Answer 11

-It is termed the master gland, since it’s hormones control most other glands.
-The pituitary consists of the posterior and anterior pituitary.
-The posterior pituitary stores and releases hormones produced by the hypothalamus.
-The anterior pituitary produces and releases its own hormones.

Question 12

What is the endocrine system?

Answer 12

-An endocrine system that produces and secretes chemical messengers (hormones), which are secreted directly into the blood. This causes more gradual responses over a longer period of time.

Question 13

How does the hypothalamus control the anterior pituitary?

Answer 13

-Neurosecretory cells in the hypothalamus produce releasing hormones.
-The releasing hormones travel down the axons of the neurosecretory cells to the pituitary stalk, and enter a capillary bed.
-The releasing hormone is then carried to another capillary bed where they stimulate the cells of the anterior pituitary to release a specific hormone.

Question 14

How does the hypothalamus control the posterior pituitary?

Answer 14

-The neurosecretory cells in the hypothalamus produce ADH and oxytocin, which travel down the axons of the neurosecretory cells into the posterior pituitary where they are stored.
-The release of these hormones from the posterior pituitary is controlled by nerve impulses from nerve cells in the hypothalamus.

Question 15

What are the hormones of the anterior pituitary?

Answer 15

-Growth hormone, prolactin, luteinizing hormone, adrenocorticotropic hormone, follicle stimulating hormone, and thyroid stimulating hormone.

Question 16

What are the hormones of the posterior pituitary?

Answer 16

-Oxytocin and antidiuretic hormone.

Question 17

What are the three parts of all neurons?

Answer 17

-Cell body, dendrites, and axon.

Question 18

What is the function of the cell body?

Answer 18

-Contains most of the neuron’s organelles, including the nucleus.

Question 19

What is the function of dendrites?

Answer 19

-Carry nerve impulses toward the cell body.

Question 20

What is the function of the axon?

Answer 20

-Carry nerve impulses away from the cell body.

Question 21

What is the structure and function of sensory neurons?

Answer 21

-Sensory neurons have long dendrites and short axons.
-They carry nerve impulses from sensory receptors to the central nervous system.

Question 22

What is the structure and function of motor neurons?

Answer 22

-Motor neurons have short dendrites and long axons.
-They carry nerve impulses away from the central nervous system to an effector.

Question 23

What is the structure and function of interneurons?

Answer 23

-Interneurons have short dendrites and short or long axons.
-They are formed within the central nervous system and conduct nerve impulses between sensory and motor neurons.

Question 24

What is the structure and function of sensory nerves?

Answer 24

-They only contain long dendrites of sensory neurons wrapped in myelin.
-They conduct nerve impulses from a sensory nerve to the central nervous system.

Question 25

What is the structure and function of motor nerves?

Answer 25

-They contain only long axons of motor neurons wrapped in myelin.
-They conduct nerve impulses from the central nervous system to an effector (muscle or gland which carries out the response).

Question 26

What are ganglia?

Answer 26

-They are groups of nerve cell bodies that lie within the central nervous system.
-Ganglia are not included within nerves since nerves only contain fibers (long axons and/or long dendrites of neurons).

Question 27

What is the central nervous system? What does it contain?

Answer 27

-The central nervous system consists of the brain and spinal cord.

Question 28

What is the location and function of the brain?

Answer 28

-The brain is found encased in the skull.
-The brain serves as the overall control center for the nervous system.

Question 29

What is the location and function of the spinal cord?

Answer 29

-The spinal cord is surrounded by vertebrae and extends down through the back of the neck, thorax, and abdomen.
-The spinal cord is the center for many reflex actions and provides a link between the brain and the peripheral nerves, which radiate out of the spinal cord.

Question 30

What does the peripheral nervous system consist of?

Answer 30

-The peripheral nervous system consists of all the nerves which radiate out from the central nervous system.
-The nerves of the P.N.S which are attached to the brain, are called the cranial nerves (21 pairs of these).
-The nerves of the P.N.S which are attached to the spinal cord are called the spinal nerves (31 pairs of these).

Question 31

What can the peripheral nervous system be divided into?

Answer 31

-Somatic and autonomic nervous system.

Question 32

What is the somatic nervous system?

Answer 32

-The somatic nervous system includes the nerves which are associated with sensory receptors (sensory neurons) and the skeletal muscles (motor neurons).
-It serves the skin, skeletal muscles, and tendons.

Question 33

What are the actions of the somatic nervous system?

Answer 33

-Some actions are voluntary, and involve the cerebral cortex, while other are involuntary, autonomic responses to stimuli.

Question 34

What actions do the sensory receptors detect as part of the somatic nervous system?

Answer 34

-The sensory receptors detect both external and internal stimuli, and the skeletal muscles act as effectors, carrying out the response to these stimuli.

Question 35

What is the main fictional unit of the somatic nervous system?

Answer 35

-The reflex arc, which is a path that nerve impulses follow during a reflex action.

Question 36

What is a reflex action?

Answer 36

-An autonomic response to a stimulus, occurs without thought

Question 37

What is the structure of the autonomic nervous system?

Answer 37

-It consists of motor neurons that control internal organs and cardiac muscle.

Question 38

What are the actions of the autonomic nervous system?

Answer 38

-The responses are involuntary and do not involve conscious control.

Question 39

What are similarities between the parasympathetic and sympathetic nervous system?

Answer 39

-Both involuntary.
-Both control all internal organs and cardiac and smooth muscle.
-Both pathways consist of two motor neurons and one ganglion.

Question 40

What is the structure of the sympathetic nervous sytstem?

Answer 40

-Consist of two motor neurons and one ganglion.
-The main neurotransmitter is noradrenaline.
-The pre-ganglionic fiber is short while the post ganglion is fiber is long. The nerves branch off the middle region of the spinal cord.

Question 41

How does the sympathetic nervous system prepare the body for emergency situations?

Answer 41

-Increasing heart rate, breathing rate, dilating bronchi and pupils, inhibits digestion by decreasing blood flow and perastalsis in the digestive tract, and activating muscles by converting glycogen to glucose.
-It also timbales the adrenal medulla of the adrenal glands to release the hormones Adrenalin and noradrenalin, which prepares the body for emergency situations (have the same reactions as listed above). The difference is they maintain the flight or fight response over a longer period of time.

Question 42

How does myelin effect the speed of a nerve impulse?

Answer 42

-In neurons that are myelinated (enclosed in a myelin coat formed by Schwann cell membranes) an action potential does not occur along section of neurons which are wrapped myelin.
-The myelin sheath is interrupted at regular intervals called the nodes of Ranvier where an action potential can occurs. Therefore in myelinated neurons an action potential jumps from one node to the next by saltatory conduction, which is very fast and results in rapid nerve impulse transmission.