UNL Human Physiology exam 3 study guide

What is the organization of the autonomic motor neurons?

Composed of the brain and spinal cord

How do autonomic neurons receive input?

From the sensory neurons to that then innervate the muscles and glands

What do association neurons do?

integrate sensory information and help direct the appropriate response to maintain homeostasis and respond to the environment

What are somatic motor neurons?

they are cell bodies in the spinal cord; it's only one neuron traveling from the spinal cord to the effector organ (skeletal muscle)

What are the types of autonomic neurons?

1.) Preganglionic neurons (first neuron)

2.) Postganglionic neurons (second neuron)

What do the preganglionic neurons do?

they have cell bodies in the brainstem or spinal cord and synapse in the autonomic ganglion

What do postganglionic neurons do?

they have cell bodies in the ganglion; however, they synapse on the effector organ (cardiac muscle, smooth muscle, and glands)

Where are autonomic ganglia located?

In head, neck, & abdomen as well as chains along either side of spinal cord

Describe how neural regulation of smooth and cardiac muscles differs from neural regulation of skeletal muscles

1.) When skeletal muscles are cut/severed they enter a state of atrophy and flaccid paralysis; when skeletal muscle is not stimulated, it loses tone

- any damage to the autonomic nerve makes its target cell even more sensitive to stimulation

2.) Cardiac muscle and some smooth muscle contract rhythmically without nerve stimulation; they maintain a resting tone

What is denervation hypersensitivity?

exaggerated response of cardiac and smooth muscle if autonomic nerves are severed

What do autonomic motor neurons do?

regulate visceral activities by either increasing (exciting) or decreasing (inhibiting) ongoing activities in their effector tissues (cardiac muscle, smooth muscle, and glands).

What do somatic motor neurons release?

acetylcholine

- this is only in skeletal muscle which is always excitatory

What to autonomic neurons release?

mainly acetylcholine and norepinephrine

- may be excitatory or inhibitory

What are the structures of the sympathetic nervous system?

1.) Thoracolumbar

- these are the preganglionic neurons that come from the thoracic and lumbar regions of the spinal cord (T1-T12 and L1 and L2)

2.) Paravertebral ganglia

- these are the preganglionic neurons that synapse in sympathetic ganglia that run parallel to the spinal cord

- these ganglia are connected, forming a sympathetic chain (trunk) or ganglia

3.) Collateral Ganglia

- many of the sympathetic neurons that don't exit the spinal cord below the diaphragm do not synapse in the sympathetic chain of ganglia, they form splanchnic nerves, which synapse in collateral ganglia

- includes celiac, superior mesenteric, and inferior mesenteric ganglia

What is convergence in the sympathetic division?

it's when several preganglionic neurons at different levels synapse on one postganglionic neuron

What can happen in the preganglionic neurons?

preganglionic neurons can branch and synapse in the ganglia at any level, this is called divergence and convergence

- it alls the sympathetic division to act as a single unit through mass activation and to be tonically active

What is divergence in the sympathetic division?

it's when one preganglionic neuron synapses on several postganglionic neurons at different levels

Explain the relationship between the sympathetic nervous system and the adrenal medulla

the adrenal medulla could be considered a modified sympathetic ganglion; secretes epinephrine and norepinephrine when stimulated by the sympathetic nervous system as a part of mass activation

- the cells of the adrenal medulla are innervated by preganglionic sympathetic fibers

What is the difference between the sympathetic and parasympathetic division of the autonomic system?

1.) Sympathetic: activates the "fight or flight" response in our body through the release of norepinephrine from the postganglionic neurons, and the secretion of epinephrine from the adrenal medulla; prepares the body for intense physical activity in emergencies

- preganglionic neurons are short (motor neurons)

2.) Parasympathetic: "rest and digest" through the release of acetylcholine from the postganglionic neurons

- preganglionic neurons are very long; only contain few specific ganglia

- Terminal ganglia (4 ganglia that the cranial nerves control)

In the parasympathetic division, what is the nerve response that controls the ciliary ganglion?

Oculomotor 3 nerve

- carries autonomic info

- preganglionic fibers exit midbrain and synapse on the ciliary ganglion

- postganglionic fibers innervate the ciliary muscles of the eye

What does the ciliary ganglia do?

controls the ciliary muscle and pupil of the eye

In the parasympathetic division, what is the nerve response that controls the pterygopalatine ganglion?

facial 7 nerve

- preganglionic fibers exit the pons and synapse in the pterygopalatine ganglion and the submandibular ganglion

What does the pterygopalatine ganglion do?

it's in charge of the lacrimal gland, nasal mucosa, pharynx, and palate

- what makes us cry

- postganglionic neurons synapse here

In the parasympathetic division, what is the nerve response that controls the submandibular ganglion?

facial 7 nerve

- preganglionic fibers exit the pons and synapse in the pterygopalatine ganglion and the submandibular ganglion

What does the submandibular ganglion do?

it's in charge of the submandibular and sublingual glands

- salivary glands

In the parasympathetic division, what is the nerve response that controls the otic ganglion?

Glossopharyngeal (IX) nerve

- preganglionic fibers synapse on the otic ganglion

- postganglionic fibers synapse on the salivary gland

What does the otic ganglion do?

controls the parotid gland

What does the vagus X nerve control and maintain?

Preganglionic fibers exit medulla, branch into several plexus and nerves, and travel to ganglia within effector organs

- Lungs, heart, liver and gallbladder, spleen, stomach, pancreas, large intestine, small intestine, kidneys, and adrenal gland

Describe the structure and innervation pathways of the parasympathetic division of the autonomic system.

Structure: craniosacral division

- preganglionic neurons come from the brain or sacral region of the spinal cord

- synapse in ganglia located near or in the effector organs (terminal ganglia)

- the preganglionic neurons do not travel with the somatic neurons like they sympathetic postganglionic neurons do

What are the neurotransmitters of the sympathetic division?

Preganglionic neurons: always ACh, cholinergic

Most postganglionic neurons: norepinephrine, adrenergic

-except for sympathetic fibers that innervate sweat glands, and blood vessels in skeletal muscles

What are the neurotransmitters of the parasympathetic division?

Preganglionic neurons: always ACh, cholinergic

Postganglionic neurons: ACh, cholinergic

Identify the hormones released by the adrenal medulla

85% epinephrine, and 15% norepinephrine

What are the sacral nerves responsible for?

Innervation to the lower part of the large intestine, rectum, and the urinary and reproductive organs

- extend from the sacral region

What is adrenergic and cholinergic synaptic transmissions?

Axons of postganglionic neurons have swellings called varicosities

- These release neurotransmitters from the axon terminal; "synapses en passant" in passing

What are the adrenergic stimulation on different organs?

Can stimulate or inhibit depending on the receptors; synapse with chromaffin cells in the medulla

Stimulation: heart, dilatory muscles of the iris, smooth muscles of many blood vessels (causes vessels constriction"

Inhibition: bronchioles in lungs, other blood vessels; inhibits contraction and causes dilation of these structures

What are the types of adrenergic receptors involved?

Alpha (1 and 2) and beta (1 and 2)

What do alpha and beta receptors act by?

G proteins and second messenger systems

What are alpha receptors sensitive to?

norepinephrine

- neurotransmitters

What are beta receptors sensitive to?

Blood epinephrine

- hormone

What adrenergic receptor is responsible for the contraction of radial fibers of the iris and dilated the pupil?

Alpha 1

What adrenergic receptor is responsible for the increase in heart rate and the strength of contraction?

Beta 1

What adrenergic receptor is responsible for the arterioles constriction due to smooth muscle contraction?

Alpha 1

What adrenergic receptor is responsible for the arterioles constriction due to sympathetic nerve activity?

Alpha 1

What adrenergic receptor is responsible for the arterioles dilating due to the hormone epinephrine?

Beta 2

What adrenergic receptor is responsible for the lungs?

Beta 2

What adrenergic receptor is responsible for the stomach and intestine?

Alpha 1

What adrenergic receptor is responsible for the liver?

Both alpha 1 and beta 2

What are the drugs that are mimic adrenergic responses?

1.) Agonists

2.) Antagonists

What do agonists drugs do?

they promote the process stimulated by the neurotransmitter

- bind to the receptor and stimulate

What to antagonist drugs do?

they block the action of the neurotransmitter

- bind to receptor and block

What are cholinergic receptors?

nicotinic and muscarinic

What are nicotinic receptors?

they are acetylcholine receptors found in the autonomic ganglia that are stimulated from the preganglionic neurons

- serve as ligand-gated ions channels for Na+ and K+

- blocked by curare

What are muscarinic receptors?

they are acetylcholine receptors found in visceral organs and stimulated by the release of acetylcholine from postganglionic neurons

- can be excitatory or inhibitory K+ or Ca 2+ channels

- use g proteins and second messenger system

- blocked by atropic

What are the nonadrenergic, noncholinergic autonomic neurons?

they do not release acetylcholine or norepinephrine

- their proposed neurotransmitters include ATP, vasoactive intestinal peptide (VIP), and nitric oxide (NO)

Why are noradrenergic, non cholinergic fibers important?

Helps in the erection of the penis

Why is Nitric Oxide important?

Because the parasympathetic neurons innervate blood vessels, causing relaxation and vasodilation (how viagra works)

- it can also produce smooth muscle relaxation in the stomach, intestines, urinary bladder, and the brain

Is ejaculation sympathetic or parasympathetic?

sympathetic

What organs are dual innervation (parasympathetic and sympathetic)?

1.) Heart: sym increases, para decreases

2.) Digestive functions: sym decreases, para increases

3.) Pupil diameter: sym dilates, para constricts

4.) Lungs: sym increases, para decreases

What are complementary effects?

occur when both divisions produce similar effects on the same target

ex. salivary gland secretion

- para stimulates watery saliva

- sym constricts blood vessels so the secretion is thicker

What are cooperative effects?

occurs when both divisions produce different effects that work together to promote a single action

ex. erection and ejaculation

- para causes vasodilation and erection

- sym causes ejaculation

ex. urination

- para aids in urinary bladder contraction

- sym helps with bladder muscle tone to control urination

What organs are innervated by the sympathetic division only?

1.) Adrenal medulla

2.) Arrector pili muscle in skin

3.) Sweat glands in skin

4.) Most blood vessels

- regulated by increase and decrease in sympathetic nerve activity

- important for body temperature regulation through blood vessels and sweats

What does the hypothalamus do in regards to regulating the medulla?

It's the major center of the ANS

- Responsible for body temperature, hunger, thirst, and the pituitary gland

What is the limbic system responsible for in regards to the medulla?

Emotional states

- blushing, pallor, fainting, cold sweating, and racing heart rate

What is the cerebellum responsible for in regards to the medulla?

motion sickness nausea, sweating, and cardiovascular changes

What is the frontal and temperol lobes responsible for in regards to the medulla?

Emotion and personality

Describe a taste bud, and where they are located

receptors on the tongue are taste buds; consists of 50-100 specialized epithelial cells with long microvilli; located on the papillae of the tongue

- olfactory (smell) influences taste (better known as gustation)

What is the papillae of the tongue?

Consists of 3 areas:

1.) Fungiform

2.) Circumvallate

3.) Foliate

What is the fungiform of the tongue?

It's the anterior (front) surface

- information travels via the facial nerve

What is the circumvallate of the tongue?

posterior surface

- information travels via the glossopharyngeal nerve

What is the foliate of the tongue?

the sides

- information travels via the glossopharyngeal nerve

How do you actually taste?

1.) Cells depolarize and release neurotransmitters on to sensory neurons

2.) Microvilli come into contact with chemicals (chemoreceptors)

3.) Each taste bud has taste cells sensitive to each category of taste

Where is the primary gustatory complex location?

both the frontal and insular lobe

What are the 5 categories of taste?

1. Salty

2.) Sour

3.) Sweet

4.) Umami (meaty)

5.) Bitter

What happens when you taste something salty?

Na+ enters the taste cell and depolarizes it

What happens when you taste something sour?

H+ enters the cell and depolarizes it

What happens when you taste something sweet or umami (meaty)?

sugar or glutamate binds to the receptor and activates G proteins/2nd- messengers to close K+ channels

What happens when you taste something bitter?

Quinine binds to a receptor, activates a G-protein/2nd messenger to release Ca 2+ into the cell

- poisons have bitter tastes

- very sensitive to low concentrations as a protective response

What are gustducins?

G proteins (protein complexes that use second messengers to produce effects) that are associated with sweet, bitter, and umami sensations

What happens in the sweet system?

Sugar activates adenylate cyclase, which produces cAMP

- other molecules may activate IP3 (inositol triphosphate) and DAG (diacylglycerol) to release Ca 2+

What are the cranial nerves that transmit taste?

1.) Fungiform (anterior side)

- facial nerve

2.) Circumvallate (posterior side)

- glossopharyngeal nerve

3.) Foliate (sides)

- also the glossopharyngeal nerve

Trace (list the steps of) the neural pathway for gustation

1.) Facial and glossopharyngeal nerves (1st order neurons)

2.) Medulla oblongata (2nd order neurons)

3.) Thalamus (3rd order neurons)

4.) Primary gustatory cortex of the insula, somatosensory cortex of parietal lobe, and prefrontal cortex

Describe the olfactory apparatus (epithelium). Where is the olfactory apparatus located?

Olfactory receptors are located in the olfactory epithelium of the nasal cavity

- The olfactory epithelium is membranous tissue located inside the nasal cavity

- Measures about 1 in squared

Explain how odorant molecules stimulate their receptors (how smell works)

1.) An odorant binds to an odorant receptor

2.) G-proteins couple to the odorant receptor

3.) The odor binding activates adenylate cyclase to make cAMP and PPi (pyrophosphate)

4.) cAMP opens Na+ and Ca 2+ channels

5.) This produces a graded depolarization which stimulates the action potential

6.) When this happens, up to 50 G-proteins may be associated with 1 receptor protein which gives sensitivity through amplification

What are olfactory receptors?

specialized nerve cells in the nose that transmit odors to the olfactory nerve

- bipolar neurons with ciliated dendrites projecting into the nasal cavity

- proteins in the cilia bind to odors

Trace (list the steps of) the neural pathway for olfaction

1.) Olfactory neurons are unmyelinated and synapse on a glomerulus in the olfactory bulb

2.) The mitral and tufted neurons of the glomeruli in the olfactory bulb synapse on the primary olfactory cortex of the frontal and parietal lobes

3.) Interconnections are made with the amygdala, hippocampus, and limbic system through the piriform cortex

4.) Prefrontal cortex also receives taste which connects the two senses

What is the piriform cortex?

memory of smell

What is special about olfactory receptors?

they synapse on a particular glomerulus; coded accordingly to which glomeruli are stimulated

- ex. a flower (complex array of odor molecules) may excite several types of odor receptors

How is odor identification improved?

lateral inhibition

- where the odor is coming from

Name the structures of the vestibular apparatus

1.) Inner ear (utricle and saccule)

2.) Semicircular canals

What does the vestibular apparatus do?

provides a sense of equilibrium

- 1.) dynamic EQ (balance utricle and saccule)

- 2.) rotational EQ (semicircular canals)

What is the vestibular apparatus?

equilibrium receptors in semicircular canals and vestibule

- made up of body labyrinth surrounding a membranous labyrinth

Where is perilymph located?

the inner ear is a system of interconnecting tunnels called labyrinths within the temporal lobe

- the tunnels are filled with a fluid called perilymph

Where is endolymph located?

membranous labyrinth

- it has an unusually high K+ concentration, which will produce depolarization (which can generate an action potential)

What type of equilibrium occurs in the utricle and saccule?

Dynamic equilibrium

What are the otolith organs?

the mechanical structures in the vestibular system that sense both linear acceleration and gravity

- each otolith organ contains an utricle, a saccule, and maculae

What type of equilibrium occurs in the semicircular canals?

Rotational equilibrium

Describe the mechanism of the sensory hair cells in the vestibular apparatus

1.) When stereocilia bend toward the kinocilium, K+ channels open, and K+ rushes into the cell and depolarizes the cell

- in endolymph

2.) Cells releases a neurotransmitter that depolarizes sensory dendrites in the vestibulocochlear nerve

- binds to 1st order neurons

3.) Bending away from the kinocilium hyperpolarizes sensory dendrites

- close of K+ ion channels is what hyperpolarizes the 1st order neuron

4.) Code for detection of direction

What does the utricle detect?

horizontal linear acceleration

What does the saccule detect?

vertical linear acceleration

What is specialized epithelium in the utricle and saccule called, and what do they do?

it's called the macula and they house hair cells

- stereocilia are embedded in a gelatinous otolithic membrane