nervous system

Question 1

neuron

Answer 1

functional unit of nervous system

Question 2

neuron structure

Answer 2

consists of several dendrites, single branches axon, and cell body (soma)

• highly specialized
• cannot divide
• dependent on glucose

Question 3

sensory (afferent)

Answer 3

receive initial stimulus from environment

Question 4

association (interneuron)

Answer 4

receive input from sensory and sent to motor neurons -make up 99% of body’s neurons

Question 5

motor (efferent)

Answer 5

from brain, stimulate target cells (effectors) to elicit response

Question 6

dendrites

Answer 6

receive information to transfer to cell body

Question 7

axon hillock

Answer 7

site of action potential gradient

Question 8

axon

Answer 8

transfer impulses away from body

Question 9

glial cells

Answer 9

capable of dividing

consist of:
1. oligodendrocytes
2. schwann cells
3. microgalia
4. ependymal cells
5. satellite cells
6. astrocytes

Question 10

oligodendrocytes

Answer 10

produce myelin in the CNS

Question 11

schwann cells

Answer 11

produce myelin in the PNS

Question 12

microglia

Answer 12

CNS phagocytes

Question 13

ependymal cells

Answer 13

circulate cerebrospinal fluid with cilia

Question 14

satellite cells

Answer 14

support cells in PNS

Question 15

astrocytes

Answer 15

physically support CNS neurons; maintain nutrient and mineral balance

Question 16

myelin sheath

Answer 16

act as insulators
separated by Nodes of Ranvier
only vertebrates have myelinated axons

Question 17

peripheral nervous system (PNS)

Answer 17

utilizes preganglionic and postganglionic axons, various neurotransmitters, and different receptors to act on the effector organs

Question 18

somatic nervous system

Answer 18

• innervates skeletal muscle
• voluntary or involuntary movements
• uses ACH at neuromuscular junctions (synapse between motor neuron and skeletal muscle cell)

Question 19

autonomic nervous system

Answer 19

sensory impulses from blood vessels, heart, chest organs, abdomen

sympathetic branch
- fight or flight
- increased blood pressure and heart rate, generation of energy
- inhibition of digestion, urination, and salivary secretion

parasympathetic branch
- rest and digest
- lowered heart rate
- increased digestion, relaxation, and sexual arousal

Question 20

central nervous system

Answer 20

• contains brain, spinal cord, and interneurons
• the blood-brain barrier is a blockade of cells that prevents or slows the passage of drugs, ions, and pathogens into the CNS –> permeable to O2, CO2, glucose, and small non-polar molecules

Question 21

Olfactory bulb (forebrain)

Answer 21

smell

Question 22

thalamus

Answer 22

relay between spinal cord and cerebral cortex

Question 23

hypothalamus

Answer 23

visceral functions
sleep, hunger, temperature regulation

Question 24

basal ganglia

Answer 24

planning/learning

Question 25

hippocampus

Answer 25

**memory**

Question 26

Limbic system

Answer 26

hippocampus, amygdala, and hypothalamus **behavioral and emotional responses**

Question 27

diencephalon subdivision

Answer 27

thalamus, hypothalamus, pineal gland

Question 28

pineal gland

Answer 28

regulates melatonin and circadium rhythm

Question 29

cerebrum

Answer 29

contains **cerebral cortex** 1. **frontal lobe** - attention 2. **parietal lobe** - sensory 3. **temporal lobe** - sound processing/interpretation 4. **occipital lobe** - visual

Question 30

midbrain

Answer 30

relay center for visual/auditory impulses **motor control**

Question 31

cerebellum

Answer 31

**balance and coordination**

Question 32

brainstem

Answer 32

connects cerebrum to spinal cord **pons** relay center (cortex + cerebellum) **medulla oblongata**

Question 33

medulla oblongata

Answer 33

controls heart rate and breathing

Question 34

resting potential

Answer 34

-70mV with K+ higher inside the cell; Na+ higher outside

Question 35

depolarization

Answer 35

* ion channel opens * Na enters and depolarizes axon * if the -50mV threshold is reached, an action potential will send Na+ down entire neuron * inside becomes more positive

Question 36

repolarization

Answer 36

* going back to resting potential * ion channel open, K+ moves out, making inside more negative

Question 37

hyperpolarization

Answer 37

* too much K+ is released * membrane potential becomes even more negative than resting

Question 38

refractory period

Answer 38

neuron unresponsive to new stimulus until the Na+/K+ pump returns ions to resting potential locations

Question 39

Na+/K+ pump

Answer 39

* maintains resting potential of -70mV using ATP * **3 Na+ out for every 2 K+ in**

Question 40

absolute refractory period

Answer 40

no additional stimuli can cause a result

Question 41

relative refactory period

Answer 41

responds if stimulus is large enough

Question 42

chemoreceptors

Answer 42

for taste, smell, blood chemistry

Question 43

transmission across a synapse

Answer 43

1. action potential reaches synaptic region 2. activates voltage-gated channels for calcium to enter 3. presynaptic neuron releases neurotransmitters from synaptic vessels to synaptic cleft 4. NTs will bind to receptors on the postsynaptic neuron 5. postsynaptic membrane is either excited or inhibited according to which NT binds

Question 44

acetylcholine (ACh)

Answer 44

* binds to ACh receptors on post-synaptic membrane for nerve transmission * secretion at neuromuscular junctions = contraction or relaxation of muscle (PNS) * recycled back to presynaptic vesicle via acetylcholinesterase --> nerve signal terminated; postsynaptic neuron cannot depolarize

Question 45

glutamate

Answer 45

most common CNS neurotransmitter in vertebrates; excitatory

Question 46

GABA

Answer 46

found in brain; inhibitory

Question 47

glycine

Answer 47

found in CNS outside brain; inhibitory

Question 48

epinephrine and norepinephrine

Answer 48

act in sympathetic nervous system bronchodilation and vasodilation to lungs and skeletal muscles vasoconstriction to the digestive system and kidneys

Question 49

if a nerve cell is stimulated below its threshold potential, what would happen

Answer 49

an action potential would NOT occur