Lecture 4: Autonomic Nervous System Flashcards
Normally both the parasympathetic and sympathetic divisions are partially active. What does this mean?
This means that their neurons continuously fire action potentials. Both divisions generally innervate the same organs but with opposite effects. This antagonism maintains homeostasis
Sympathetic division increases:
heart rate and respiration rates and inhibits digestion and elimination
Parasympathetic division decreases
heart and respiratory rates and allows digestion and elimination of waste
Most visceral organs have dual innervation
What does this mean?
Both AND divisions are partially active, resulting in a sympathetic and parasympathetic tone. Usually, one division predominates, but in a few cases, they have a cooperative effect
What is an Antagonistic Interactions
The parasympathetic division promotes
Maintenance functions and conserves body energy. It dominates during rest.
it is sometimes called the Rest and Disgest system - keeps body energy as low as possible and promotes housekeeping functions
The parasympathetic division
Parasympathetic division dominates:
Heart and smooth muscle of digestive tracts and urinary tract organs and activates most glands except for:
Adrenal glands and sweat glands
Can the parasympathetic division override the parasympathetic tone?
Yes, during times of stress
Drugs that block the response of the parasympathetic nervous system work by:
Increasing heart rate and causing urinary and fecal retention
Describe the sympathetic division
Mobilizes the body during activity. It dominates in exciting or threatening situations. Mobilizes energy stores and prepares for physical activities (three Es: exercise, Excitement and Emergency)
What are the 3 Es of the sympathetic nervous system?
- Exercise
- Excitement
- Emergency
What is another name of the sympathtic nervous system?
Flight or flight system
Almost all blood vessel smooth muscle is entirely innervated by
sympathetic fibres only. This division controls blood pressure at rest
when the temperature rises, the sympathetic nerves will:
- dilates skin blood vessels
- activates sweat glands
what is the purpose of dilating blood vessels in response to increasing temperature?
allows heat to escape
What happens to blood vessels when the body temperature drops?
the constrict
What is the purpose of constricting blood vessels when the body’s temperature drops?
It enables the body to shunt blood to the internal vital organs to protect them
In the sympathetic division of the nervous system ____ is released frim the kidneys
renin
What does the release of renin from the kidneys do?
increases blood pressure
What are the metabolic effects of the sympathetic nervous system
- increased heart rate
- Raises blood glucose levels
- mobilizes fats for use as fuels
What is the reponse of the sympathetic nervous systems to dropping blood pressure?
If blood pressure drops, sympthetic fibers called vasomotor fibres fire faster than normal to increase constriction of blood vessels and cause blood pressure to rise
What is the response of the sympathetic nervous system to increasing blood pressure?
If the blood pressure rises, vasomotor fibres fire less than normal causing less constriction (dilation) of vessles = decrease in blood pressure
= alls sympathetic system to shunt blood where it is needed
Nicotinic Receptors are ionotripic or Metabotropic?
Ionotropic
Muscarinic Receptors are Ionotropic or metabotropic?
metabotropic
Name 2 types of cholinergic receptors:
- Nictonic Receptors
- Muscarinic Receptors
when bound, cholinergic receptors mimic
ACh effects
what are the first two steps in se
