Lecture 14: Autonomic and Endocrine Systems Flashcards
What does the PNS consist of?
all nervous tissue outside of CNS
Cranial nerves - 12 pairs
Spinal nerves - 31 pairs - radiate out from the spinal cord
Ganglia - mass of nervous tissue (cell bodies) switching stations
Peripheral Nerves into peripheral tissues
What does the CNS consist of?
Brain and Spinal Cord (which are connected by the Foramen Magnum)
What does the CNS process?
CNS processes many kinds of sensory info and is the source of -thoughts, emotions and memories
What are sensory neurons?
Afferent neurons
autonomic/somatic receptors detect stimuli and collect information
respond to information inside and outside our body
via Cranial and Spinal Nerves
What are Motor neurons?
Efferent neurons
Not under voluntary conscious control
Somatic (voluntary) –> skeletal muscle
Autonomic(involuntary) –> sympathetic or parasympathetic –> cardiac muscle, smooth muscle, glands
What is the role of nerves?
Hardwired mechanism which coordinate our actions and bodily functions through collecting information and sending signals out
What do autonomic motor neurons control?
Involuntary muscle
e.g.: Cardiac muscle, Smooth muscle, Glands
What is the role of axons?
transmits APs along the neuron
very long as they need to take information a really long distance before they terminate the information
What is the role of the myelin sheath?
insulating layer
What is the role of dendrites?
To radiate out of the cell body/nucleus and receive APs
What are the 5 steps to nerve impulse transmission?
Occurs rapidly in course of milliseconds
- Nerve impulses travel down presynaptic neuron
- Opens voltage gated Ca2+ channels, which changes its structure(proteins in axon terminal cell wall) due to voltage change
- Influx of Ca2+ promotes vesicles (containing neurotransmitters) to empty into the synaptic cleft by fusing with the membrane and releasing neurotransmitters
- Neurotransmitter binds to ligand gated SODIUM channels/receptor on post synaptic neuron- causing influx of Na2+
- Voltage changes and Conducts a nerve impulse down post synaptic neuron (dendrites–>cell body–>axon)
What do unmyelinated nerves look like?
They have Schwann cells associated with it but not wrapped insulation around them
What are nerve impulses?
Electrochemical signals
Rapid moving voltage
What is the Autonomic Nervous system?
Self governing system
How has a the sympathetic system evolved?
Evolved to help respond to particularly dangerous or threatening situations
What is the sympathetic division?
Responses associated with Exercise, Emotion and Excitement
What response in included in the sympathetic division?
The alarm response
“fight , fright or flight response”
In what areas of the body does the autonomic NS affect?
Heart Eyes Mouth Lungs Skin Gut
What change occurs in the Heart during the Alarm response?
Increased rate
Increased force of contraction
so blood can move through up to 5 times faster with more force
What change occurs in the Eyes during the Alarm response?
Pupils are dilated
- more (sensory) aware of your surroundings
- get information more quickly and easily
What change occurs in the Mouth during the Alarm Response?
Decrease in saliva
-aids digestion which is not required so energy is used elsewhere
What change occurs in the Lungs during the Alarm response?
Dilated Bronchi
allow more O2 into the body
What change occurs in the Skin during the Alarm Response?
Constrict Peripheral Blood vessels - pushes blood to muscles and key areas - lighter skin colour
Contract erector pili muscles - hairs stand on end/look threatening
Increased sweet secretion - more evaporation-heat removed/cool surfaces
What changes occur in the Gut during the Alarm Response?
Decrease Digestion
-digestion is an energetic long term process so it would be wasteful
What additional changes occurs to the blood during the Alarm Response?
Increased Blood Sugar- needed for respiration(muscles to move to fight or flee) from liver
Increase BP and Increased Water Retention - transport is fast by the water retention - release a loss of blood in potential damage in fight
What response in included in the parasympathetic division?
The relaxation response
What is the parasympathetic division?
Responses associated with - Repletion, Rest and Relaxation
What changes occur in the Heart during the Relaxation Response?
Decrease rate
Decrease force of contraction
What changes occur in the Eyes during the Relaxation Response?
Pupils contract
What changes occur in the Mouth during the Relaxation Response?
Increased Saliva
-regeneration activities such as - digestion and -repair
What changes occur in the Lungs during the Relaxation Response?
Constrict Bronchi
-dont take in as much oxygen into the body as we are relaxing
What changes occur in the Skin during the Relaxation Response?
Dilate Peripheral blood vessels
-allows more blood into tissues and cellular areas