overview of nervous system

Question 1

the nervous system is divided into two parts, what are they?

Answer 1

central nervous system (CNS) and peripheral nervous system (PNS)

Question 2

the PNS contains:

Answer 2

• afferent neurons (sensory)
• efferent neurons (motor)

Question 3

describe afferent neurons

Answer 3

• sensory neurons
• carry signals to the brain
• carries signals to the CNA from sensory organs

Question 4

describe efferent neurons

Answer 4

• motor neurons
• carry signals away from the brain
• carries signals from the CNS that control the activities of muscles and glands

Question 5

the efferent portion of the PNS is further divided into…

Answer 5

• somatic nervous system (voluntary skeletal muscle)
• autonomic nervous system (involuntary organ, gland, and smooth muscle response)

Question 6

describe the CNS

Answer 6

• receives and processes information, initiates action
• includes the brain and spinal cord

Question 7

describe the brain

Answer 7

receives and processes sensory info; initiates responses; stores memories; generates thoughts and emotions

Question 8

describe the spinal cord

Answer 8

conducts signals to and from the brain; controls reflex activities

Question 9

describe the PNS

Answer 9

• transmits signals between the CNS and the rest of the body
• includes afferent (sensory) and efferent (motor) neurons

Question 10

describe the autonomic nervous system

Answer 10

• part of the PNS, functions in homeostasis, stress response, and body tissue repair
• controls involuntary responses by influencing organs, glands, and smooth muscle
• divided into sympathetic (adrenergic) and parasympathetic (cholinergic) divisions
• maintains homeostasis and equilibrium in the body
• balance effects/maintains normal functioning
• all systems innervated by both components
• sympathetic and parasympathetic have opposite effects on the organs/tissues they innervate
• drugs can stimulate or block through their receptors

Question 11

describe the sympathetic division of the autonomic nervous system

Answer 11

• prepares body for stressful or energetic activity
• “fight or flight”
• adrenergic receptors (alpha and beta)

Question 12

describe the parasympathetic division of the autonomic nervous system

Answer 12

• dominates during times of rest and digestion
• “rest and digest”
• directs maintenance activities
• cholinergic receptors

Question 13

describe body responses when the parasympathetic division is activated

Answer 13

• constricts pupils
• stimulates salivation
• slows heart
• constricts bronchioles
• stimulates digestion
• stimulates gallbladder
• contracts bladder
• stimulates sex organs

Question 14

describe body responses when the sympathetic division is activated

Answer 14

• dilates pupils
• inhibits salivation
• accelerates heart
• dilates bronchioles
• inhibits digestion
• stimulates release of glucose
• secretes epinephrine and norepinephrine
• relaxes bladder
• inhibits sex organs

Question 15

what are the primary neurotransmitters

Answer 15

• norepinephrine (derived from dopamine)
• acetylcholine

Question 16

what is the key difference between neurotransmitters and neurohormones

Answer 16

• neurotransmitters are chemical messengers used by the nervous system to transmit nerve impulse across the synapses
• neurohormones are chemical messengers used by the endocrine system to stimulate/communicate with specific target cells

Question 17

define ligands

Answer 17

• neurotransmitters/medications/hormones can bind ti receptors in the ANS
• the rate of binding is called “affinity”
• can be agonists or antagonists

Question 18

define affinity

Answer 18

rate of binding of ligands that demonstrates a tendency or strength of the effect

Question 19

define agonists

Answer 19

a ligand that alters receptor function and triggers a physiological response

Question 20

define antagonists

Answer 20

a ligand that binds to a receptor but fails to active a physiological response or blocks another response

Question 21

define signal transduction

Answer 21

cascade of intracellular events that occur when receptors located on target tissues are stimulated by a ligand