ANAPHY FINALS ANS Flashcards
Causes contraction of skeletal muscles
Voluntary
Somatic Nervous System
Controls cardiac and smooth muscle and glands
Involuntary
Helps maintain homeostasis
Autonomic Nervous System
What does ANS primarily innervates?
Internal organs
Two divisions of Ans
Sympathetic and Parasympathetic Nervous System
What type of innervation that most organs receive from both divisions?
Dual innervation
What does the Sympathetic Division of the Autonomic Nervous System do?
It responds to a threat to our homeostasis or stress and enables survival
-increases oxygen delivered to our skeletal muscles
-increases sweating
-blood is shifted away from the digestive system and toward the skeletal muscle
-pupils dilate
-brain becomes alert
What does the parasympathetic division of the autonomic nervous system do?
Active when body is not stressed or under a threat
“Rest and digest”
-lacrimation
-salivation
-digestion
-urination
-defecation
-sexual arousal
What are the synapses of ANS?
Cholinergic
Adrenergic
What is the cholinergic synapse?
Acetylcholine (ACh) is a nerotransmitter released
What is the adrenergic synapse?
Norepinephrine
Types of Cholinergic Receptors
Nicotinic and Muscarinic
Endogenous ligand- acetylcholine
Exogenous ligand- nicotine
Chemically gated ion channel
Nicotinic
Endogenous ligand-acetylcholine
Exogenous ligand-muscarine
Trigger changes in cell without allowing ions to pass through membrane
Muscarinic
It depolarizes postsynaptic cell; causes contraction or a new action potential
Nicotinic
It can have excitatory effects or inhibitory effects ; it is not an ion channel so does not directly affect membrane potential
Muscarinic
It is located in the adrenal medulla, all skeletal neuromuscular junctions, postganglionic neurons throughout the ANS, some CNS synapse
Nicotinic
It is located at all target tissues of the parasympathetic nervous system
Muscarinic
Types of adrenergic receptors
Alpha and Beta receptors
Located in skin, GI and pelvic organs, and blood vessels
Causes contraction of smooth muscles
a1
Found in pancreas, platelets, brain, and spinal cord
-ihibit insulin release
-promote blood clot
a2
Found in heart and kidney
- increase heart rate, force of contraction, and secretion of renin
b1
Found in blood vessels, lungs, uterus, stomach, and small intestines
- cause relaxation of smooth muscles
b2
Found in adipose tissue
-breakdown of lipids
b3
Used at cholinergic synapses
Acetylcholine
Used at adrenergic synapses
Epinephrine and norepinephrine
Helps maintain internal homeostasis
Autonomic Reflexes
Why is autonomic reflex important? It maintains parameters like?
Blood Pressure
Heart rate
Airway diameter
Digestive activity
Autonomic reflex arcs are similar to
Somatic reflex arcs
_____ are smooth in cardiac muscle, smooth muscle, and glands
Effectors
What are the structure of reflexes?
Afferent branch
Efferent branch
Afferent branch
Single neuron
Sensory info comes from _____, ______, and ________
Somatic, special senses, and viscera
Some _____ sensations are not consciously perceived
Visceral
Efferent branch
Two neurons
Preganglionic neurons synapses with _____ in a ganglion
Postganglionic neurons
Projects to target tissue
Postganglionic neuron
Combinations of sympathetic and parasympathetic axons
Autonomic plexuses
Types of autonomic plexus
Cardiac
Pulmonary
Esophageal
Abdominal aortic
Subdivisions in autonomic plexus (abdominal aorta)
Celiac, inferior mesenteric, superior mesenteric, and hypogastric plexus
These 3 receive only sympathetic innervation
Blood vessels, sweat glands, arrector pili muscles
Lower heart rate, increased GI activity, pupil dilation, airway constriction, decrease breathing rate
Parasympathetic dominance
Increased heart rate, decreased GI activity, pupil constriction, airway dilation, increased breathing rate
Sympathetic dominance
Balance between sympathetic and parasympathetic dominance when an organ is at rest
Autonomic Tone
Dominates the heart at rest
-lowers heart rate to normal range
Parasympathetic tone
Dominates blood vessels at rest
-adjusts constriction of vessels to maintain blood pressure
Sympathetic tone
______ helps body response to stress
Autonomic Nervous System
The aim is to increase nutrients in blood and deliver more blood to head and muscles
ANS
Stress response results in:
- Lipid breakdown and increased blood glucose
- Airway dilation for increased oxygen in blood
- Increased blood flow to skeletal muscles ; decreased blood flow to viscera
- Higher blood pressure to increase speed of delivery to brain and muscles
It helps in stress
Endocrine hormones
