Bio 251 Exam 2
Central Nervous System (CNS) - ✅✅ -brain and spinal cord
-control and command center of the body
Peripheral Nervous System (PNS) - ✅✅ -the sensory and motor neurons that
connect the central nervous system (CNS) to the rest of the body.
-outside the CNS
-consists of nerves extending from brain and spinal cord
-peripheral nerves link all regions of the body to the CNS
-includes SOMATIC, AUTONOMIC, and SENSORY nervous systems
autonomic nervous system (ANS) - ✅✅ -The part of the PNS that controls smooth
muscle, cardiac muscle, glands, and adipose (fat) cells in organs.
-involuntary control
-there are two divisions of the ANS:
sympathetic and parasympathetic nervous system
What does dual innervation of the autonomic nervous system mean? - ✅✅ -That
both the sympathetic and parasympathetic nervous systems are both regulating
organs to maintain homeostasis.
-parasympathetic and sympathetic actives OPPOSE each other
-if ones speeds up, the other speeds down
-these systems are constantly being adjusted an altered
-it depends on what organ it is if the sympathetic and parasympathetic increases or
decreases activity
ex. when you are exercising your sympathetic nervous system speeds up your heart
rate and pumps more blood. when you are just sitting, your parasympathetic nervous
system slows down your heart rate and pumps less blood
What is the anatomy of the autonomic nervous system? - ✅✅ -1. there are
pathways of two neurons (pairs) from the CNS to the organs (connected in series)
these are the preganglionic neurons and postganglionic neurons
2. the autonomic ganglia is where the synapse happens between the pre and post
ganglionic neurons.
3. Then the axons of the postganglionic neurons innervate the target organs (effector
organs)
✅✅
Where do the preganglionic neurons originate in the sympathetic nervous system? -
-in the thoracic and lumbar regions of the spinal cord
Anatomy of the sympathetic nervous system - ✅✅ -1. short pregangilonic neurons
to sympathetic chain ganglia (along vertebral column)
2. most ganglia are linked together in a sympathetic chain
, 3. long postganglionic neurons from chain to effector organs
4. a few preganglionic axons travel to collateral ganglia (not part of chain ganglia)
✅✅
What is the exception to the anatomy of the sympathetic nervous system? -
-There is no postganglionic axons so the adrenal medulla secretes epinephrine
and it gets carried throughout the bloodstream
✅✅
In the sympathetic nervous system, what neurotransmitter do the preganglionic
neurons release? - -acetylcholine (Ach)
✅✅
What receptor does acetylcholine bind to on the postganglionic cell? -
-cholinergic receptors
-this causes an action potential
✅✅
in the sympathetic nervous system, what neurotransmitter do the postganglionic
neurons release? - -norepinephrine (NE)
✅✅
What receptor does norepinephrine bind to on the target cells of the organ? -
-adrenergic receptors
What are the two types of adrenergic receptors? - ✅✅-alpha and beta
What are the properties of alpha adrenergic receptors? - ✅✅--they are the most
common type
-found in many different tissues/organs
-usually excitatory
-affinity is greater for norepinephrine than epinephrine
-so, tissues with alpha receptors have a dominant effect
What are the properties of beta 1 adrenergic receptors? - ✅✅--located primarily in
the cardiac muscle
-usually exciatory
-has equal affinity for norepinephrine and epinephrine
What are the properties of beta 2 adrenergic receptors? - ✅✅--located in some
blood vessels and smooth muscle
-usually inhibitory
-greater affinity for epinephrine
What are the properties for beta 3 adrenergic receptors? - ✅✅--located in adipose
tissue (fat)
-usually excitatory
-equal affinity for norepinephrine and epinephrine
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