Exam 2 Physiology- UCF Ahangari

Autonomic Nervous System

composed of parasympathetic nervous system and sympathetic nervous system

purpose of the autonomic nervous system

exerts control over the functions of many organs and tissues in the body

What does the ANS innervate?

smooth muscle, cardiac muscle, glands

What pathways does ANS have?

afferent and efferent

Location of efferent fibers

have their cell bodies in the spinal cord

Where doe efferent fibers reach?

the sympathetic ganglia on both sides of the vertebral column

Where do the parasympathetic efferents reach?

on the ganglia at or near the organs

function of sympathetic nervous system

"Fight or Flight" Reactions for emergencies, Expenditure of Energy

function of parasympathetic nervous system

Control the body's response while at rest.

Pheochromocytoma

a benign tumor of the adrenal medulla that causes the gland to produce excess epinephrine

Organization of the autonomic nervous system

1. Synapses between neurons are made in the autonomic ganglia.

2. pre-ganglionic neurons have their cell bodies in the central nervous system, and synapse in autonomic ganglia.

3. post ganglionic neurons of both divisions, have their cell bodies in autonomic, ganglia and synapse on effector organs.

4. adrenal medulla is a specialized ganglion of the sympathetic nervous system pre-ganglionic fibers, synapse directly on chromaffin cells in the adrenal medulla.

What does chromaffin secrete?

80% epinephrine and 20% norepinephrine

Another name for the sympathetic nervous system

thoracolumbar

sympathetic origin

T1-L2 lateral horn

parasympathetic origin

Cranial nerve three, cranial, nerve, seven, cranial nerve, nine, cranial, nerve 10, and S1 to S3

Sympathetic system receptors

Adrenergic receptors :

Alpha receptors: α-1 and α-2

Beta receptors: β-1 and β-2

Dopamine receptors: D1 and D2

Parasympathetic system receptors

Cholinergic receptors, nicotinic receptors, muscarinic receptors

What do adrenergic neurons release?

norepinephrine

What do cholinergic neurons release?

ACh

What do peptidergic neurons release?

substance P, vasoactive intestinal peptide (VIP)

alpha one receptors location

Are located on vascular, smooth muscle of the skin, and splanchic regions, the gastrointestinal and bladder, sphincter, and the radial muscle of the iris

What receptor is equally sensitive to norepinephrine and epinephrine?

Alpha one receptor

Alpha two receptor location

Located, and pre-synaptic, nerve terminals, platelets. Fat cells, and the walls of the G.I. tract.

What do Alpha two receptors produce?

Relaxation or dilation

Beta one receptor location

Are located in the SA node, AV node, and ventricular muscle of the heart

Beta one receptor produces...

Excitation (increased heart rate, increase, conduction, velocity, and increase contractility)

What receptor is more sensitive than alpha one receptors?

Beta one receptor

Beta two receptor location

Located on vascular smooth, muscle of skeletal muscle, bronchial smooth muscle, and the walls of the G.I. tract and bladder

Beta two receptors are more sensitive to...

Epinephrine than to norepinephrine

nicotinic receptors location

Are located in the autonomic ganglia of the sympathetic and parasympathetic, nervous systems, at the neuromuscular junction, and in the adrenal medulla

What are nicotinic receptors activated by?

ACH or nicotine

What do nicotinic receptors produce?

They produce excitation.

What are nicotinic receptors blocked by?

Blocked by ganglionic blockers in the autonomic ganglia, but not at the neuromuscular junction

Where are muscarinic receptors located?

Located in the heart, smooth, muscle and glands.

What are muscarinic receptors activated by?

ACh and muscarine

What are muscarinic receptors blocked by?

Atropine

What is the medulla responsible for?

Vasomotor center, respiratory center, swallowing, coughing, and vomiting centers

What is the Pons responsible for?

Pneumotaxic center

Midbrain responsibility?

Micturition center

Purpose of the hypothalamus?

its body's thermostat, detects cooling or heating, activates mechanisms to cool or heat down body to regulate temp. and homeostasis

The preganglionic is associated with what receptor?

ACH

The postganglionic is associated with what receptor/receptors?

Sympathetic: ACH

Parasympathetic: Norepinephrine

What is the purpose of sensory systems?

Are specialized epithelial cells, or neurons that transduce environmental signals into neural signals.

What are the environmental signals that can be detected by the sensory systems?

Mechanical force, lights, sounds, chemicals, and temperature.

Mechanoreceptors

Respond to mechanical stimulus

location of mechanoreceptors

Pacinian corpuscles, joint receptors, stretch receptors in muscle, hair cells in auditory and vestibular systems, baroreceptors in carotid sinus

Photoreceptors are located in..

Rods and cones of the retina

Chemoreceptors are....

olfactory receptors, taste receptors, osmoreceptors, carotid body O2 receptors

What receptors are associated with extremes of temperature and pain?

nociceptors

Fiber type with the fastest conduction velocity?

A-alpha

What is A-beta responsible for?

touch and pressure

What is A-delta responsible for?

touch, pressure, temperature and pain

What has the slowest conduction for a fiber?

Postganglionic autonomic fibers

Receptive field

the stimulus region and features that affect the activity of a cell in a sensory system

First order neurons

-are the primary afferent neurons that receive the transduced signal and send the information to the CNS. Cell bodies of the primary afferent neurons are in dorsal root or spinal cord ganglia.

second order neurons are located in

spinal cord or brain stem

Purpose of second order neurons

Receive information from one or more primary afferent neurons in relay nuclei and transmit it to the thalamus.

Third order neurons are located in

the relay nuclei of the thalamus.

Fourth order neurons are located

in the appropriate sensory area of the cerebral cortex

Purpose of fourth order neurons

The information received results in conscious perception of the stimulus.

What are the somatosensory pathways?

dorsal column system and anterolateral system

types of somatosensory receptors

mechanoreceptors, thermoreceptors, nociceptors

What does the dorsal column system do?

processes sensations of fine touch, pressure, two point discrimination and vibration

What does the anterolateral system do?

processes sensations of temperature, pain and light touch.

What does destruction of thalamic nuclei result in?

Results in loss of sensation in the controateral side of the body.

Pain is associated with

The detection and perception of noxious stimuli

What are the receptors for pain?

free nerve endings in the skin, muscle, and viscera

What fibers are associated with fast pain?

Alpha delta fibers

What fibers are associated with slow pain?

C fibers

slow pain can be associated with

Aching, burning, or throbbing

An example of referred pain is

Ischemic heart pain is referred to the chest and shoulder

What is the two-point touch threshold?

If each point touches the receptive fields of different sensory neurons, two separate points of touch will be felt. If both caliper points touch the receptive field of one sensory neuron, only one point of touch will be felt.

Gustation

sense of taste

Olfaction

sense of smell

Gustation and Olfaction are

A category of chemoreception

Sense of taste is transduced by

Tastebuds

facial nerve (cranial nerve VII)

Taste sensations from the anterior 2/3 of the tongue and soft palate

Cranial nerve nine carries

Taste sensations from the posterior 1/3 of the tongue

Ageusia

inability to taste

glossodynia

burning sensation of the tongue

Benign migratory glossitis

irregular and inflamed patches on the tongue surface that often have white borders. Cause unknown.

Olfactory receptor cells are located

olfactory epithelium

Anosmia

Lack of smell

Phantosmia

"hallucinated smell", often unpleasant

Dysosmia

distorted sense of smell

Sclera

maintains the shape of the eye and protects the delicate inner layers of tissue; the white of the eye

Structures of the Eye

sclera, choroid, retina

The eye can distinguish two qualities of light:

brightness and wavelength

choroid

The middle thin layer of the eye and provides oxygen and nourishment to the outer layers of the retina.

Retina

The third or the inner layer of the eye. Lays over the back 2/3 of the choroid coat.

____ are very sensitive to light and do not see color.

Rod cells

______ are sensitive to different wavelengths of light, and that is how we are able to tell different colors.

Cone cells

Blind spot is known as

optic disc

fovea centralis

Where cone cells are densely packed

Pigment epithelial cell

absorb stray light and prevent scatter of light

Bipolar cells

Synapse on ganglion cells

If the neurotransmitter is excitatory

Then the response of the bipolar horizontal cell to light is hyperpolarization

If the neurotransmitter is inhibitory

The response of the bipolar or horizontal cell to light is depolarization

color blindness

May occur because of the eye, nerve, or brain damage, or due to exposure to certain chemicals.

Night blindness

Maybe caused by vitamin A deficiency.