m3 + 4 lect. - efferent pathways

Question 1

what are efferent pathways?

Answer 1

motor pathways

Question 2

what happens in the somatic motor cortex?

Answer 2

location: precentral gyrus, frontal lobe
- origination of most skeletal motor activity
- nerves form the pyramidal tract - travels down the brainstem and spinal cord

Question 3

through where is motor activity refined?

Answer 3

in the cerebellum through the input of proprioceptors - spinocerebellar tract (coordinates activity)

Question 4

what neurotransmitter controls efferent pathways?

Answer 4

dopamine (primary)
- at brain stem level
- lack of this causes loss of intentional control ex) tremors - Parkinson’s

those who do crack or cocaine have higher chances of Parkinson’s

Question 5

what kind’s of actions does the somatic nervous system control?

Answer 5

voluntary actions

Question 6

what is the reason for the autonomic nervous system?

Answer 6

to maintain homeostasis

Question 7

aspects of the autonomic nervous system?

Answer 7

• involuntary actions
• controls visceral activities: blood flow, HR, digestion, RR, hormones, etc.
• centered in the hypothalamus, pons, medulla oblongata

Question 8

what are the two divisions of the autonomic nervous system?

Answer 8

• parasympathetic nervous system - “rest and digest”
• sympathetic nervous system - “fight or flight”

Question 9

aspects of parasympathetic nervous system?

Answer 9

“rest and digest”
- causes dec. of physical activity
- inc. visceral activity (digestion, metabolism)
- long preganglionic axon, short postganglionic axon
- secretes: acetylcholine (cholinergic = wet, inc. glandular activity)

Question 10

aspects of sympathetic nervous system?

Answer 10

fight or flight
- short preganglionic axon, long postganglionic axon
- secretes: norepinephrine (neurotransmitter), epinephrine (hormone)

Question 11

what cranial nerves does the parasympathetic nervous system?

Answer 11

CN 3, 7, 9, 10
- vagus nerve carries 90%

Question 12

ANS: aspects of sympathetic nervous system (thoracolumbar) T1 - L3?

Answer 12

• main use: prepare us for action
• fight or flight
• uses nor-epi as main neurotransmitter (adrenergic - dry, drug type that affects SNS)
• made bigger by epinephrine

Question 13

ANS: sympathetic nervous system receptors?

Answer 13

Beta 1 - excites cardias muscle (makes heart beat faster),
- stimulates lipolysis (to make energy)
- beta blocker - prevents elevated HR

Beta 2 - inhibits smooth muscle of viscera
- dilates blood vessels
- bronchioles to increase blood and air flow

Question 14

autonomic NS changes in the sympathetic nervous system:

Answer 14

• inc. HR, BP, RR ( blood flow inc. towards skeletal muscle and skin)
• dilates bronchioles = inc. airflow
• pupil dilation = see clearer
• stimulates arrector pili muscles = goosebumps
• inc. sweating = thermoregulation
• dec. glandular activity in digestive system (dry)
• dec. digestive activity
• orgasm

Question 15

ANS: parasympathetic nervous system receptors?

Answer 15

nicotinic - excitatory to all ganglionic nerves in ANS or somatic NS at neuromuscular junction (skeletal muscle)

muscarinic - excitatory to all PSNS target tissues but inhibits cardiac muscle, smooth muscle, glands

Question 16

autonomic NS changes in the parasympathetic nervous system?

Answer 16

• dec. HR, BP, RR (less O2 needed, bc at rest)
• constricts bronchioles = dec. airflow
• pupil constriction = sleepiness
• inc. glandular secretions of digestive system
• inc. digestive activity
• erection of penis, clitoris
• initiates micturition (urination), emesis, defecation