CHAPTER 8 Central Nervous System ANSWERS

P. Complete the following statements. 1. The limbic system encircles the top of the ________. 2. The limbic system influences ________ and ________ behaviors. 3. This behavior is modified by the ________. 4. A part of the limbic system is the ________ bulb, which explains why the sense of ________ is associated with emotions.

1. brain stem 2. unconscious ; instinctive 3. cerebral cortex 4. olfactory ; smell

M. Label the lobes of the cerebrum

1. frontal 2. temporal 3. parietal 4. occipital

H. Describe in detail each of the three meninges, including the roles.

Dura mater- (outside layer) tough, dense membrane of fibrous connective tissue connecting an abundance of blood vessels. Arachnoid- (middle layer) resembles a fine cobweb with fluid-filled spaces. Pia mater- (covers brain surface) consists of blood vessels held together by fine areolar connective tissue.

D. Using the following words and symbols, complete the story on nerve functions. A STORY OF HOW A NERVE CELL FUNCTIONS (NERVES-R-US) In our day-to-day lives, we do not stop to think about all the processes going on in our magnificent machine, the body. The heart pumps, blood circulates, and air moves in and out. we jog, talk, reason, and carry out activities of daily living. We look here at just one of these incredible functions. To understand how impulses (________) are carried along nerves, we need to know about membrane ________. Think of the nerve cell membrane as an envelope around the ________ with lots of openings or ________. Some of these channels are open and allow ________ to move (leak) back and forth inside and ________ during cell activity. Some of these openings are closed and ________ only on special occasions. These closed channels are called ________. Another special channel is called the sodium-potassium pump. It maintains the flow of ions from areas of ________ concentration to ________ concentration and serves to restore the cytoplasm and the ________ fluid to their original states. You may think you have a lot to worry about, but think about the special channel. We have leaky ones that allow ions to flow in and out; we have gated channels that are open only on special occasions, and we have the sodium-potassium pump. When the nerve cell is just hanging out, resting, the ion of ________(potassium) and ________ (sodium) are where they are supposed to be. Inside the nerve cell are ________ amounts of K+ and ________ amounts of Na+. The ________ is true in the extracellular fluid that has more Na+ ions that K+ ions. During this time, some K+ cells sneak out through the membrane, which then makes the inside of the nerve cell more ________. Now we have a situation in which the environment inside the cell is more negative than the environment outside the cell. This state of affairs is called resting membrane potential, and the membrane is said to be ________. This is where the fun begins! A sensory receptor picks up a message, a stimulus such as a sound, and the stimulus energy is converted to a(n) ________ signal. if it is strong enough, it will ________ a portion of the cell membrane. This is the special occasion that causes those gated channels to open, initiating the ________-________. The sodium ions in the extracellular fluid line up and march through the gated channel into the cytoplasm. Now the insides of the cell is more ________. The membrane potential is reserved, and the gates close to additional sodium ions. Well, wait a minute. There are too many ions here, so the special potassium gates open and large amounts of potassium leave the cytoplasm of the cell, which results in the ________ of the membrane. To restore order to this mess, the ________-________ pump gets into act and ________ the original concentrations of sodium and potassium ions. A simpler way of saying all this is that upon stimulation, a nerve cell goes from resting potential to depolarization and then to repolarization and back to resting potential. Although this action occurs in just one part of the cell membrane, it spreads to ________ membrane regions, continuing away from the original site of the stimulation, sending messages over the nerves. The nervous system is an electrical conduction system; sometimes we use such phrases as "sparks are flying." This could really be true. It is hard to imagine that this cycle is completed millions of times in a minute.

stimuli excitability cytoplasm channels ions outside open gated higher lower extracellular K+ NA+ large small reserved negative polarized electrical depolarize action-potential positive repolarization sodium-potassium restores adjacent

B. 1. Label the following diagram of neuron. 2. What are the roles of axon and dendrite?

1) 1. dendrites 2. soma 3. nucleus 4. axon 5. myelin sheath 6. synaptic knob ? 7. axon terminals 8. axon 9. cell body 10. axon 2. Axon carries impulses away from the cell body and toward another neuron. Dendrites receive impulses from other neurons and carry them to the cell body.

R. List at least two symptoms and one treatment for the following: 1. Meningitis 2. Epilepsy 3. Essential tremors 4. Parkinson's Disease 5. Brain tumor

1. symptoms: headache, fever, and stiff neck treatment: depending on the cause, may get better on its own. or could be life-threatening, requiring antibiotic treatments 2. symptoms: abnormal behaviors and sensations, unconscious treatments: medications, sometimes surgery, devices, and dietary changes 3. symptoms: shaking occurs with simple tasks; stress, fatigue, caffeine treatment: medications such as beta blockers 4. symptoms: tremor in one hand, slow movement, stiffness, loss of balance treatments: medications 5. symptoms: strong headaches, blurred vision, loss of balance, confusion treatments: surgery, radiation, and chemotherapy

Q. Select the letter of the choice that best completes each statement. 1. In Parkinson's disease, a person exhibits a shuffling gait, tremors, and muscular rigidity. This disease is thought to be caused by a decrease in 2. The nerve cell sheaths are destroyed in 3. An inflammation of the brain is known as 4. Epilepsy is characterized by recurring and excessive discharge of neuron activity. Seizures are said to be the result of 5. A bypass or shunt operation that diverts the cerebrospinal fluid is treatment for 6. In multiple sclerosis, a symptom called nystagmus is 7. Cerebral palsy is a disturbance in voluntary muscle action. he most pronounced symptom is spastic paralysis that involves 8. An injury to the spinal cord at the C-2 level may result in 9. Mild cognitive impairment is usually a symptom of the ________ stage of Alzheimer's disease. 10. A subdural hematoma is a collection of blood between the ________ of the brain.

1. B (dopamine) 2. D (multiple sclerosis) 3. B (encephalitis) 4. A ( spontaneous, uncontrolled cycles of electrical activity) 5. B (hydrocephalus) 6. C (tremorous movement of the eye) 7. D ( the arms and legs on both sides of the body) 8. D (quadriplegia) 9. C (third) 10. B (dura mater and arachnid layer)

L. Match the descriptions in Column B with the terms in Column A.

1. D 2. G 3. K 4. I 5. J 6. A 7. B 8. C 9. H 10.

F. Match the words in Column A with the related items in Column B.

1. E (brain and spinal cord) 2. C (cranial and spinal nerves) 3. A (ganglia and peripheral nerves) 4. B (12 pairs) 5. D (31 pairs)

K. 1. sulci and gyri 2. cerebral parietal lobe and occipial lobe 3. hippocampus and parahippocampus 4. thalamus and hypothalamus 5. pons and medulla

1. Sulci is a groove of furrow, especially on the surface of the brain. / Gyri is a ridge or fold between two sets on the cerebral surface in the brain. 2. Cerebral parietal lobe is located behind the frontal lobe. Receives and interprets nerve impulses from sensory receptors for pain, touch, heat, cold, etc. / Occipital lobe- located over the cerebellum, houses the visual area controlling eyesight 3. Hippocampus involves memory and learning, recognizes new info and recalls spatial relationships. / Parahippocampus helps monitor strong emotions like rage and fright. 4. Thalamus is a spherical mass of gray matter. Acts as a relay station for incoming and outgoing nerve impulses. / Hypothalamus is part of the limbic system and considered the 'brain' of the brain. Stimulates the pituitary to release hormones. 5. Pons is located in front of the cerebellum, between the midbrain and medulla. Serves a two-way conductive pathway for nerve impulses between cerebrum, cerebellum, and other areas. / Medulla is a bulb-shaped structure found between pons and spinal cord. Serves as a passageway for nerve impulses between brain and spinal cord.

C. Circle the correct word or words in each following statements. 1. (Associative neurons, efferent neurons) carry impulses from the sensory neurons to the motor neurons. 2. The extension of the neuron that carries the messages away from the away from the nerve cell body is the (axon, dendrite). 3. The type of nervous tissue that insulates and supports the nerve is called "nerve glue" or (neuroglia, neuron). 4. (Conductivity, irritability) is the ability of a neuron to react to stimuli. 5. Neurons that carry messages to the brain and spinal cord are (afferent, efferent) neurons. 6. Oligodendrocytes are (central nervous system, peripheral nervous system) structures that wrap around neuronal axons to form the myelin sheath. 7. The extensions of the neuron that take messages to the cell body are called (axons, dendrites). 8. The two main communication systems of the body are the nervous system and the (endocrine, circulatory) system. 9. The myelin sheath (speeds up, slows down) an impulse as it travels along the axon. 10. Neurons that carry messages from the brain and spinal cord are called motor or (afferent, efferent) neurons.

1. associative neurons 2. axon 3. neuroglia 4. irritability 5. afferent 6. central nervous system 7. dendrites 8. endocrine 9. speeds up 10. efferent

J. 1. What is the role of the choroid plexus in the blood-brain barrier? 2. What is the result of an inflammation of the cranial meninges? 3. What is a lumbar puncture? What is the purpose?

1. is in contact with the cells lining the ventricles, helping the formation of the CSF. 2. increased secretion of CSF which collects in the confined bone cavity of the brain and spinal column 3. Lumbar puncture is the procedure of taking fluid from the spine in the lower back through a hollow needle. Purpose is for diagnostic purposes, such as diseases.

E. In the following statements, circle the item that makes each statement correct. 1. A nerve cell has (one, two, three) axon(s). 2. Dendrites carry messages (from, to) the cell body. 3. A (synapse, synaptic) cleft is the area where messages go from the axon of one cell to the dendrite of another. 4. An impulse travels along a(n) (dendrite, axon) tot eh end where the neurotransmitter is released. 5. The neurotransmitter between muscle cells and nerve cells is (epinephrine, acetylcholine).

1. one 2. to 3. synaptic 4. axon 5. acetylcholine

A. 1. List the major functions of the central nervous system. 2. Compare the roles of the nervous system and the endocrine system in coordinating and integrating body activities.

1. receives messages from stimuli all over the body, the brain interprets the message, and the brain responds to the message and carries out an activity. 2. They both maintain homeostasis. However time is the big difference. Endocrine- slow, long term effects. Nervous- fast, short term effects.

I. 1. Describe where cerebrospinal fluid is formed. 2. What is the function of cerebrospinal fluid? 3. Describe the pathway of cerebrospinal fluid.

1. ventricles of the brain; choroid plexus 2. serves as a liquid shock absorber protecting the delicate brain and spinal cord. 3. 1- CSF is secreted by choroid plexus into each lateral ventricle 2- Flows through interventricular foramen into third ventricle 3- Choroid plexus in third ventricle adds more CSF. 4- Flows down cerebral aqueduct to fourth ventricle. 5- Choroid plexus and fourth ventricle adds more CSF 6- Flows out into lateral apertures and one median apertures 7- Fills subarachnoid space and bathes external surfaces of brain and spinal cord 8- At arachnoid villi, CSF is reabsorbed into venous blood of dural venous sinuses.