The Nervous System

Question 1

what is the role of the nervous system?

Answer 1

to transmit information rapidly

Question 2

What are the 3 main steps in the the nervous system pathway?

Answer 2

1. detection of stimulus
2. Processing in brain
3. response in other part of body

Question 3

What are the physical components/parts of the first step: detection of stimulus

Answer 3

• sensory receptors
• afferent/sensory neurons

Question 4

What are the components of the second step: Integration?

Answer 4

central nervous system
(brain & spinal cord interneurons)

Question 5

what are the components of the third step: motor outpur?

Answer 5

• efferent/motor neurons
• effector cells (muslce cells or glands)

Question 6

what’s in the central nervous system?

Answer 6

• brain
• spinal cord

Question 7

what’s in the peripheral nervous system?

Answer 7

• afferent (sensory) neurons
• efferent (motor) neurons
• ALL neurons outside of CNS are PNS

Question 8

what are the two divisions of the peripheral nervous system?

Answer 8

the sensory (afferent) division and the motor (efferent) division

Question 9

What are the two sensing environments of the sensory (afferent) division?

Answer 9

the external and internal environment

Question 10

What are the two parts of the motor (efferent) division?

Answer 10

autonomic nervous system and the somatic nervous system

Question 11

What are the two divisions of the autonomic nervous system?

Answer 11

parasympathethic division and sympathetic division

Question 12

what senses sense the external environment?

Answer 12

somatic and special sense

Question 13

what senses sense the internal environment?

Answer 13

visceral senses

Question 14

what do somatic senses detect - examples?

Answer 14

skin, muscle, joints

Question 15

what do special senses detect - examples?

Answer 15

vision, hearing, smell, taste, equilibrium (balance)

Question 16

what do visceral senses detect - examples?

Answer 16

• fullness of stomach
• blood pressure
• blood volume
• oxygen levels

Question 17

where do exteroreceptors detect stimuli?

Answer 17

outside the body

Question 18

where do interoreceptors detect stimuli?

Answer 18

within the body

Question 19

what is an effector cell?

Answer 19

a cell that carries out the body’s response to a stimulus

Question 20

what is motor output

Answer 20

the conduction of signals from integration centers to effector cells

Question 21

what does the stomatic nervous system do?

Answer 21

responds to external and internal stimuli by sending signals to skeletal muscles (VOLUNTARY)

Question 22

what does the autonomic nervous system do?

Answer 22

responds to stimuli by sending signals to smooth muscle, cardiac muscle and organs of the body

Question 23

what does the sympathetic nervous system do?

Answer 23

• prepares the body for stress ( increase heart rate, rate of gas exchange, glucose metabolism)
• inhibits digestive and excretory systems

Question 24

what does the parasympathetic nervous system do?

Answer 24

• restores body to normal balance - calming
• stimulates digestive and excretory systems (salivary glands, stomach, intestine, pancreas, bladder)
• decreases heart rate, and rate of gas exchange in lungs

Question 25

what affects the sympathetic nervous system?

Answer 25

epinephrine / norepinephrine

Question 26

what affects the parasympathetic nervous system?

Answer 26

acetylcholine

Question 27

what is a nerve?

Answer 27

a group of neurons bundled together

Question 28

what is a neuron

Answer 28

a nerve cell - the structural and functional unit of the nervous system

Question 29

what is an excitable cell?

Answer 29

a cell capable of producing large, rapid electrical signals - a change in membrane protential

Question 30

what are examples of excitable cells?

Answer 30

neurons & muscle cells

Question 31

mature neurons lose the ability to undergo cell division

Question 32

what are the components of a neuron?

Answer 32

- cell body (soma) - dendrites - axon (nerve fiber) - axon hillock - synaptic terminal

Question 33

describe the cell body (2 points)

Answer 33

- the main part of the cell - contains the nucleus and organelles

Question 34

describe the dendrties visually

Answer 34

short, branched, extensions

Question 35

describe the axon

Answer 35

- long extension that can branch - only one per neuron

Question 36

describe the axon hillock

Answer 36

where the axon originates

Question 37

describe the synaptic terminal

Answer 37

ends of axons

Question 38

what is the function of the cell body?

Answer 38

to carry out basic cell functions (protein synthesis, metabolism)

Question 39

what is the function of the dendrites?

Answer 39

receives input from other neurons

Question 40

what is the function of the axon?

Answer 40

to send information

Question 41

what is the function of the axon hillock?

Answer 41

where the action potential initiates

Question 42

what is the function of the synaptic terminal?

Answer 42

to contain or release neurotransmitters

Question 43

what are the steps/direction of signal conduction within a neuron?

Answer 43

dendrites -> cell body -> axon hillock -> axon -> synaptic terminal

Question 44

what are the types of neurons?

Answer 44

- sensory neurons - interneurons - motor neurons

Question 45

what is an afferent neuron?

Answer 45

a sensory neuron

Question 46

what does a sensory neuron do?

Answer 46

carries signals from sensory receptors to CNS

Question 47

what is a ganglia?

Answer 47

a cluster of neurons

Question 48

what is an association neuron?

Answer 48

an interneuron

Question 49

what does an interneuron do?

Answer 49

receives incoming signals from sensory neurons and delivers outgoing signals to neurons responsible for responses

Question 50

an interneuron can be excitatory or inhibitory

Question 51

what is an efferent neuron?

Answer 51

a motor neuron

Question 52

what does a motor neuron do?

Answer 52

carries signal from CNS to effector cells

Question 53

what does an effector cell do?

Answer 53

responds according to what was detected like muscle contractions and gland secretion of hormones

Question 54

what consists of 90% of the nervous system?

Answer 54

glial cells

Question 55

what do glial cells do?

Answer 55

provide structural and metabolic support to neurons

Question 56

what are the types of glial cells? Are they part of the CNS or PNS?

Answer 56

- astrocytes (CNS) - oligodendrocytes (CNS) - schann cells (PNS)

Question 57

how is an astrocyte shaped?

Answer 57

star-shaped

Question 58

what do astrocytes do?

Answer 58

- provide structural and metabolic support for a neuron - communicates with neurons

Question 59

Does the astrocyte have electrical conduction?

Answer 59

NO

Question 60

describe the blood brain barrier?

Answer 60

- the blood vessels in the brain are completely sealed off with the help of astrocytes

Question 61

what do the oligodendrocytes and schwann cells do?

Answer 61

they wrap themselves around the axon of a neuron to provide insulation for electrical impulses passign through the axon

Question 62

what forms the myelin sheath?

Answer 62

oligodendrocytes and schwann cells

Question 63

descrine the traits of the myelin sheath?

Answer 63

- cell membranes have a lot of lipid molecules which are poor electrical conductors to provide electrical insulation

Question 64

what is a neurilemma?

Answer 64

myelin sheaths wrapped around each other

Question 65

what are nodes of ranvier?

Answer 65

gaps between cells that wrap themselves around the neuron

Question 66

what are the types of nerve circuits?

Answer 66

- divergent nerve circuit - convergent nerve circuit - circular nerve circuit

Question 67

what is the direction of the impulse conduction?

Answer 67

transmitting cell - presynaptic cell (axon of neuron) -> synapse -> target cell - postsynaptic (dendrite of neuron or effector cell)

Question 68

describe a divergent nerve circuit

Answer 68

nerve impulse in one presynaptic neuron leads to nerve impulses in SEVERAL postsynatptic neurons

Question 69

describe a convergent nerve circuit

Answer 69

nerve impulse in SEVERAL presynaptic neurons leads to ONE nerve impulse in the postsynaptic neuron

Question 70

what is an example of a divergent nerve circuit?

Answer 70

visual information sense by photoreceptors sent to several parts of the brain

Question 71

what is an example of a convergent nerve circuit?

Answer 71

information from several sources like vision, touch and hearing is used to identify an object in the environment

Question 72

what is an example of a circular nerve circuit?

Answer 72

processing and storing of memories

Question 73

what is the simplest nerve circuit?

Answer 73

a reflex arc

Question 74

what is a reflex arc?

Answer 74

a type of nerve circuit that regulates the reflex

Question 75

what is a reflex?

Answer 75

rapid, involuntary response to stimuli

Question 76

where does intergration occur for a reflex arc?

Answer 76

in the spinal cord rather than in the brain