What happens when muscarinic receptors are activated?
it can be excitatory or inhibitory; effects K+ permeability; effects target tissue permeability to k+; increase K+ permeability, then more K+ leaves tissue; decrease K+ permeability, then less K+ leaves tissue
What are the effects of parasympathetic activation
1. constriction of airways
2. constriction of pupils
3. decreased metabolic rate
4. decrease in heart rate and bp
5. increase in smooth muscle contraction
6. increase in activity in urinary system
7. increase blood flow to reproductive organs
8. increase in nutrient absorption
9. increase in secretion in digestive glands
Where will sympathetic preganglionic fibers originate?
originate at T1-L2
Are sympathetic preganglionic fibers long or short?
What are the 3 major classes of sympathetic ganglia?
1. sympathetic chain ganglia
2. collateral ganglia
3. adrenal medulla
How many of eacy type of ganglia are found within the sympathetic chain?
-innervates small intestine & proximal 2/3 of large intestine
3. inferior mesenteric ganglia
-innervates 1/3 of large intestine, kidney, bladder, reproductive organs
How does neurotransmitter release within the adrenal medulla differ from other two?
provides bodywide response; allows for sympathetic activation everywhere, instead of just one or two tissues
Will sympathetic postganglionic fibers be long or short?
What is the sympathetic division also known as?
What are the functions of the alpha receptors?
1. alpha1 increases release of ca2+ from sarcolemmic reticulum; increases smooth muscle contraction
(ex: pupil dilation)
2. alpha2 lowers cAMP levels, usually an inhibitory effect
-cyclicAMP, 2nd messenger, causes increase of enzyme activity and/or depolarization
-decrease in cAMP will decrease enzyme activity and decrease depolarization
What are the functions of each class of beta receptor?
1. Beta1: increase HR, increase force of contraction, increased metabolic rate, increase lipolysis (fat breakdown), beta blockers effect; decrease BP
2. Beta2: albuteral beta2 agonist; airway dilation; drug used for asthma; relaxation of smooth muscles(airways, digestive & urinary tracts); blood vessel dilation; increase diameter, increase in digestive and urinary tracts
3. Beta3: only found in adipose tissue; increases fat breakdown
What type of receptor is on the sympathetic postganglionic neurons?
What type of neurotransmitter will sympathetic postganglionic neurons release?
What class of receptor is on the target tissue within the sympathetic division?
What are the effects of sympathetic activation?
1. Dilation of pupils
2. Increased heart rate and BP
3. Dilation of respiratory passages
4. Increased sweating
5. Increased rate of respiration
6. Decreased rate of digestion
7. Decreased urinary activities
8. Decreased blood flow to reproductive organs
9. Increased metabolic rate
10. Increased mental alertness
Why is dual innervation important?
opposing effects from the two systems innervate most of the body tissues