UNIT 10- NERVOUS SYSTEM

Question 1

What happens on day 14 after conception?

Answer 1

Embryo split into 3 germ layers- ectoderm, mesoderm and endoderm

Question 2

What happens on day 20 after conception?

Answer 2

formation of neural tube- develops into brain and spinal cord

Question 3

What happens on week 4 after conception?

Answer 3

organizes in 3 bulges: prosencephalon, rhombencephalon and mesencephalon

Question 4

What happens on week 5 after conception?

Answer 4

bulges organized into 5 regions: telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon

Question 5

What produces CSF?

Answer 5

Choroid plexus

Question 6

Central sulcus divides ________ and _________ lobes, whereas lateral sulcus divides __________ from ____________

Answer 6

Central sulcus divides parietal and frontal lobes, whereas lateral sulcus divides temporal lobe from parental and frontal lobes

Question 7

Precentral vs postcentral gyri

Answer 7

Precentral gyrus- voluntary muscle movement (part of frontal lobe)
Postcentral gyrus- somatosensory info from body (part of parietal lobe)

Question 8

Functions of the 5 cerebral lobes

Answer 8

1. Frontal- voluntary motor control
2. Parietal- somatosensory
3. Occipital- vision
4. Temporal- auditory
5. Insula- memory and pain

Question 9

UMNs of precentral gyrus synapse on ________ which is relayed to _________ and __________ which form the ______________

Answer 9

UMNs of precentral gyrus synapse on basal nuclei which is relayed to thalamus and cerebellum which form the accessory motor system (how rapid a movement will occur and how large the movement will be)

Question 10

What is the function of the limbic system and how does the fact that there are no connections between limbic and cerebral cortex affect the function?

Answer 10

The limbic system is responsible or emotion, motivation, LTM and smell
The fact that there are no connections between limbic and cerebral cortex demonstrates why humans do not have conscious control over emotions

Question 11

Mesencephalon is made up of…(4)

Answer 11

1. Corpora quadrigemina- visual auditory reflexes
2. Cerebral peduncles- ascending and descending tracts
3. Red nucleus- connect cerebrum to cerebellum, motor coordination
4. Substantia nigra- dopaminergic nigrostriatal system

Question 12

Ascending afferent nerves are involved in _______ processes and innervate the ________ root, whereas descending efferent nerves are involved in ________ processes and innervate the _______ root. These combine to form ____________ nerve

Answer 12

Afferent nerves are involved in sensory processes and innervate the dorsal root, whereas efferent nerves are involved in motor processes and innervate the ventral root. These combine to form peripheral spinal nerve

Question 13

What are the 2 major ascending tracts? What are the 2 major descending tracts?

Answer 13

Ascending (sensory) tracts:
1. Spinothalamic- pain, temp
2. Spinocerebellar- sensory, proprioceptive info
Descending (motor) tracts:
1. Pyramidal- voluntary motor control
2. Extrapyramidal- involuntary motor control

Question 14

What are the 3 requirements of a reflex arc?

Answer 14

1. sensory receptor to detect stimulus and sensory neuron to transmit signal to spinal cord
2. motor neuron to transmit involuntary response to effect/target
3. an effector organ for response

Question 15

What is the flexor reflex?

Answer 15

reflex in response to painful stimuli

Question 16

Nerves that innervate skeletal muscle are _______ and ________, whereas nerves that innervate smooth muscle, cardiac muscle and glands are _________ and ___________

Answer 16

Nerves that innervate skeletal muscle are somatic and voluntary, whereas nerves that innervate smooth muscle, cardiac muscle and glands are autonomic and involuntary

Question 17

There are ___ cranial nerves and ___ spinal nerves

Answer 17

12 cranial, 31 spinal

Question 18

What is the structure of somatic motor neurons? What is the structure of autonomic motor neurons?

Answer 18

Somatic motor neurons- cell body is located in the CNS, axon innovates skeletal muscle (voluntary)

Autonomic motor neurons- involves 2 neurons. First neutron (preganglionic) has cell body in the grey matter of spinal cord axon synapses with second neuron (postganglionic) whose axon innervates the effector/target organ (involuntary)

Question 19

In the sympathetic division myelinated preganglionic axons exit the _________ in______ of spinal nerve. Unmyelinated postganglionic axons travel to __________ as part of the spinal nerve.

Answer 19

In the sympathetic division myelinated preganglionic axons exit the spinal cord in ventral roots of spinal nerve. Unmyelinated postganglionic axons travel to effector/target organs as part of the spinal nerve.

Question 20

What system stimulates the adrenal medulla to secrete epinephrine and norepinephrine?

Answer 20

Sympathetic NS stimulates the adrenal medulla to secrete NE and epinephrine

Question 21

Parasympathetic preganglionic fibers originate in ________ and synapse in ganglia located ____________ or _______ innervated organs which supply postganglionic fibers that synapse with __________

Answer 21

Parasympathetic preganglionic fibers originate in BRAIN and synapse in ganglia located NEXT TO or IN innervated organs which supply postganglionic fibers that synapse with EFFECTOR CELLS

Question 22

What is the major structural difference between sympathetic and parasympathetic innervation of target areas?

Answer 22

In the sympathetic division, the ganglion cells are typically outside the target organ in parasympathetic the ganglion cells are inside or next to the target organ

Question 23

What is the MAIN difference between the somatic and autonomic divisions of the motor PNS division?

Answer 23

ANS neurons do NOT directly innervate their target area, they require a two neuron circuit for the motor response (and autonomic ganglia as a relay station)

Question 24

Sympathetic cells make…
Parasympathetic cells make…

Answer 24

Sympathetic cells make norepinephrine
Parasympathetic cells make acetylcholine

Question 25

What are the 2 main classes of adrenergic receptors and what are the differences between them?

Answer 25

Beta receptors (B1, B2, B3)- produce effects by stimulating production of cAMP in target cells. Promote smooth muscle relaxation and cardiac muscle contraction
Alpha receptors (A1 and A2)- produce response by stimulating rise in cytoplasmic calcium concentration. Promote smooth muscle contraction

Question 26

Vasoconstrictor effect of sympathetic nerves is a result of _________ receptor activation

Answer 26

a1 adrenergic receptor activation

Question 27

What are the 2 main types of cholinergic receptors and what are the differences between them?

Answer 27

Nicotinic receptors- located in neuromuscular junction of skeletal muscle. They re ligand gated ion channels, when open Na+ in K+ out causes depolarization and excitatory response

Muscarinic receptors- coupled to G proteins, can be excitatory or inhibitory

Question 28

Adrenergic stimulation is a part of _____________ system. Cholinergic stimulation is a part of _____________ system.

Answer 28

Adrenergic stimulation is a part of sympathetic system. Cholinergic stimulation is a part of parasympathetic system.