Autonomic Nervous System Flashcards
What involuntary activities does the autonomic NS control?
Smooth muscle
Cardiac muscle
Various glands
What are the two divisions of the autonomic nervous system
Sympathetic NS
Parasympathetic NS
What preganglionic neurons are present in the brainstem
CN 3,7,9 - head structures CN 10 (vagus) - thoracic and abdominal organs
What preganglionic neurons are present in the sacral spinal cord
S2,3,4 - pelvic organs
Where are preganglionic neurons T1-L2 present
Thoracic and lumbar regions of the spinal cord
Describe neuron organisation in the Parasympathetic NS
Long preganglion neuron
Short postganglion neuron
Ganglion near or in effector
Describe neuron organisation in the Sympathetic NS
Pre and post ganglion neurones similar in length
What is a ganglion
A collection of cell neurones working at the synapse
What organs does the Parasympathetic NS affect
Salivary gland and heart
What anabolic effects does the Parasympathetic NS have
Storing energy - digestion
Slowing heart
What in the body is affected by the Parasympathetic NS
Iris and ciliary muscle Lamina and salivary glands Heart (SA node) Bronchi GI Tract Bladder Genitalia
Describes the actions the Parasympathetic NS has on the body
Discrete actions on single organs
Describe the actions the Sympathetic NS has on the body
Widespread actions, often affecting the whole body
How does the Sympathetic NS affect the body
Distribution of sympathetic nerves
Circulating adrenaline
Homeostasis - blood pressure, adrenaline
Fight, flight or fright
What in the body is affected by the Sympathetic NS
Iris Blood Vessels Heart Bronchi Adrenal Medulla GI Tract Bladder Genitalia
What are the effects of ANS activity
Smooth muscle - blood vessels, bronchi
Heart - GI Tract, rate of contraction
Glands - salivary glands, GI glands, sweat glands
Does the ANS control breathing
No - breathing muscles are skeletal muscles controlled by somatic nerves eg - phrenic nerves
How do sympathetic and parasympathetic nerves affect the iris
S - Contraction
P - Contraction
How do sympathetic and parasympathetic nerves affect the ciliary muscle
S - Relaxation
P - Contraction
How do sympathetic and parasympathetic nerves affect the salivary glands
S - Secretion (viscous, low volume)
P - Secretion (copious, watery)
How do sympathetic and parasympathetic nerves affect the lacrimal glands
S - Secretion
P - Secretion
How do sympathetic and parasympathetic nerves affect the nasal glands
S - None
P - Secretion
How do sympathetic and parasympathetic nerves affect blood vessels
S - Constriction of Alpha
Dilation of Beta
P - None
What effect does noradrenaline have
Contraction of smooth muscle in blood vessels (vasoconstriction) - alpha receptor
Relaxation of bronchial sm (bronchodilaton) - beta receptor
