Human Physio Topic 8
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- What are the two parts of the autonomic system?
- Sympathetic and parasympathetic
- What is the definition of Efferent Divison?
- a communication link by which the CNS controls activities of effector organs (e.g., muscles, organs, glands, etc.)
- Autonomic is a/an _______ branch vs Somatic is a/an _______ branch.
- involuntary; voluntary
- What are effector organs?
- -receive the signal from CNS -muscles, glands, adipose tissue
- What does our somatic system control?
- skeletal muscles
- What is the Autonomic NS Primary Function?
- to regulate the function of effector organs in order to maintain homeostasis
- What is the adrenal medulla?
- a modified sympatheic ganglion that secretes hormones into blood when stimulated. -in Sympathetic only
- Where does the sympathetic NS originate?
- tharacic (chest) & lumbar (abdominal) regions of spinal cord
- In the Autonomic NS, what is the common structure for both sympathetic and parasympathetic NS?
- 1. Every pathway has 2 neuron chains 2. Cell body of 1st neuron lies w/in CNS 3. Axon synapses w/ cell body of 2nd neuron in chain in a ganglion 4. Axon of 2nd neuron innervates the effector organ
- What are the characteristics of the Parasympathetic only?
- -routine housekeeping -most active during rest -originate in brain (cranial) and sacral (pelvic) areas of CNS -Ganglia close to effector organs
- Neurotransmitters: Sympathetic
- 1. 1st neuron releases Acetylcholine 2. 2nd neuron releases norepinephrine 3. adrenal medulla releases epinephrine into blood -SO: onto effector organs --> releases norepinephrine & epinephrine
- Neurotransmitters: Parasympathetic
- 1. 1st neuron releases ACh 2. 2nd neuron releases ACh -SO: onto effector organs --> releases ACh
- Response of effector organs to sympathetic and parasympathetic depend on what?
- effector organ & its receptors & neurotransmitters
- When the body is stressed, what are the relative contributions of the sympathetic and parasympathetic nervous systems?
- Both are active but the sympathetic is dominant.
- Acetylcholine receptors
- -located on 2nd neuron -on membrane of effector organs
- When the sympathetic NS dominates what happens?
- "Fight or Flight" response -blood vessels constrict (alpha binding to norepin.) -heart dilated (beta-2) -dilate blood vessels to skeletal muscles (beta 2) -Increase heart rate and force of contraction (Beta 1) -Airways dilate (Beta 2) -Liver releases glucose (B2) -Pupils dilate (alpha)
- What happens when the Parasympathetic is Dominant?
- "Rest & Digest" "housekeeping" functions (digestion, etc) -decreases heart rate -increase GI motility -Stimulate GI secretions -Relax GI sphincters -Contract airways to lungs -Pupils constrict -Eye muscles contract for near vision
- Lou Gehrig's Disease
- -Progressive disease -motor neurons die -brain and spinal cord affected -APs randomly fire and cause uncontrollable visible contractions -voluntary muscle control affected -Early symptoms: muscle weakness -Later stages: paralysis -"mind" unaffected -2 per 100,000 people -throughout world -10% family history -Causes of sporadic form not known -50% of patients die w/in 2 yr of diagnosis -Lou Gehrig, Stephen Hawking