PHED-2506EL Chapter Notes - Chapter 14: Defecation, Brainstem, Ejaculation
25 Jun 2018
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Chapter 14 Objectives
1. Contrast ANS with the SNS
These differ in 3 areas:
SNS ANS
Effectors Skeletal muscle Cardiac muscle, smooth
muscle, and glands
Efferent pathways Axons extend from CNS to
effector
Two-neuron chain;
-The preganglionic neuron
-The (post) ganglionic
neuron that extends to an
effector organ
Target organ responses All somatic neurons release
Ach which gives an
excitatory effect
Preganglionic neurons
release Ach
Postganglionic neurons
release Ach or
norepinephrine and the
effect is either excitatory or
inhibitory
2. List the similarities and differences between the parasympathetic and sympathetic
pathways.
Sympathetic Parasympathetic
Differences -Fight or flight
- Activated in threatening,
exciting or emergency
situations
-Promotes adjustments
during exercise: blood flow
to muscles are increased
- Rest and digest
- Keeps body energy as low
as possible
-Blood pressure, respiratory
rates and heart rates are low
-GI tract activity is high
-Skin is warm and pupils
are constricted
Similarities: -Both systems are controlled by the autonomic nervous system thus the
actions of these systems are not voluntary commands.
-Both work towards homeostasis
3. List the different receptor types and where they can be found.
Cholinergic Receptors: -Ach –releasing receptors
-2 types of Ach binding receptors
Nicotinic: found on motor end plates, all post ganglionic neurons, and the
hormone producing cells of the adrenal medulla
Muscarinic: found on all effector cells stimulated by postganglionic cholinergic
fibres
Adrenergic Receptors: -2 types
-Alpha and Beta
-Both found on organs that respond to norepinephrine (NE)
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Document Summary
Chapter 14 objectives: contrast ans with the sns. The (post) ganglionic neuron that extends to an effector organ. Postganglionic neurons release ach or norepinephrine and the effect is either excitatory or inhibitory: list the similarities and differences between the parasympathetic and sympathetic pathways. Activated in threatening, exciting or emergency situations. Promotes adjustments during exercise: blood flow to muscles are increased. Keeps body energy as low as possible. Blood pressure, respiratory rates and heart rates are low. Similarities: -both systems are controlled by the autonomic nervous system thus the actions of these systems are not voluntary commands. Both work towards homeostasis: list the different receptor types and where they can be found. Nicotinic: found on motor end plates, all post ganglionic neurons, and the hormone producing cells of the adrenal medulla. Muscarinic: found on all effector cells stimulated by postganglionic cholinergic fibres.
