Chapter 14 (lectures)

1. Sympathetic

2. Parasympathetic

1. Sympathetic

2. Parasympathetic

Two divisions of the autonomic nervous system

Adjust visceral function

Primary role of autonomic nervous system

1. Smooth muscle

2. Cardiac muscle

3. Glands

What does does the autonomic nervous system innervate? [3]

1. Adjsut blood pressure and blood flow

2. Speed up or slow down heart rate

3. Change body temperature

4. Increase stomach secretions

5. Alter pupil dilation {etc….}

What can the autonomic nervous system do? [5]

Somatic has single neuron from CNS to effector organ.

Autonomic has two neuron chain from CNS to effector.

How many neurons in somatic vs. autonomic nervous system?

Somatic: ACh

Autonomic: ACh and Norepinephrine

Neurotransmitters in somatic vs. autonomic nervous system

Somatic: excitation only

Autonomic: excitation and inhibition

Effect of neurotransmitters in somatic vs. autonomic nervous systen

Somatic: heavily myelinated axons insulate and signal does not leak out (faster)

Autonomic: relatively slower because axons are light/not myelinated

Relative speed in somatic vs. autonomic nervous system

Adrenal medulla

Part of autonomic system goes directly to which gland to stimulate it to release hormones?

Parasympathetic division

Division of ANS that promotes maintenance functions and conserves bod energy. “Rest and digest,” after fight or flight

Sympathetic nervous system

Division of ANS that Mobilizes body during activity. “Fight or Flight.” Gets body ready to respond to high stress/activity

Arises from brain and sacral region. All fibers come from brain stem and sacral region

Origin point of the parasympathetic nervous system

Arises from thoracic and lumbar regions

Origin point of sympathetic nervous system

Very near, sometimes within, visceral organs

Where are ganglia located in parasympathetic nervous system?

Very close to the spinal cord

Where are ganglia located in sympathetic nervous system?

They generally innervate most (the same) visceral organs, and have mainly opposite (antagonistic) interactions. Usually one division dominates in a given situation.

Describe interactions between sympathetic and parasympathetic nervous systems:

Sympathetic: increase heart rate, dilate airways inhibit digestion and eliination

Parasympathetic: Restore heart rate, restore airway diameter, ensure body fueling and waste elimination occurs as needed.

Sympathetic vs. parasympathetic responses to stress

1. Swat glands

2. Adrenal medulla

3. Arrector pili muscles

4. Coronary blood vessels of heart

5. Blood coagulation

6. Cellular metabolism

7. Adipose tissue

Glands/organs that are NOT innervated by the parasympathetic division (no effect) [7]

Control of blood vessels

Sympathetic division dominates…

Control of heart and smooth muscle of digestive and urinary tract

Parasympathetic division dominates…

1. Most blood vessels

2. Sweat glands

3. erector pili muscles

4. Kidneys

5. Adrenal medulla

Unique roles of the sympathetic division (only have sympathetic fibers) [5]

Vasomotor tone

Innervation by the sympathetic nervous system causing continual low levels of contraction

Vasodilation

Decreased firing of signals in sympathetic division causing blood vessel diameter to increase and decrease blood pressure

Vasoconstriction

Increased firing of signals in sypathetic division causin blood vessel diameter to decrease and increase blood pressure

Controls body temperature

Unique homeostatic mechanism that is only controlled by sympathetic nervous system (hint: sympathetic innervates sweat glands and blood vessels)

Tends to slow heart rate, maintains normal activity level of digestive system and urinary tract . Sympathetic still innervates, but only in times of stress

Parasympathetic effect on heart and digestive tract:

Neurotransmitter

Chemical messengers that are leased at a synapse between neurons (or neuron and effector organs)

Which binding receptor, different receptors for different effector organs

What determines effect of neurotransmitters in ANS?

1. Cholinergic receptors

2. Adrenergic receptors

Two broad categories of receptors in ANS

Cholinergic receptors

Receptors in ANS that bind to ACh

Adrenergic receptors

Receptors in ANS that bind to norepinephrine

1. Nicotinic

2. Muscarinic

Two types of cholinergic receptors

Nicotinic receptor

ACh binds to this receptor and is an excitor

Muscarinic

ACh binds to this receptor and is EITHER inhibitory or excitatory

1. Alpha receptors

2. Beta receptors

Two types of adrenergic receptors that can be either inhibitory or excitatory

Hypothalamus oversees everything autonomic is doing and integrates it. Because of this integration, hypothalamus can coordinate heart activity, BP, bod temperature, water balance, and endocrine activity.

How does hypothalamus control autonomic nervous system?

Cerebral cortex is linked. We can consciously do things like controlling breathing, because the cortex is linked into hypothalamus and control of visceral functions.

How can we consciously control autonomic function?