BM 267 Test 2

CH. 9,10,11,12

which tissues doe the ANS innervate?

• smooth

• cardiac

• glands

How does its control differ from voluntary motor control?

ANS control is involuntary

Where does the intervening synapse occur in the autonomic motor pathway from the CNS to target organ?

peripheral (outside the brain and spinal cord) autonomic ganglion

How many neurons link the CNS to an effector in somatic motor pathways

one motor neuron

How many neurons link the CNS to an effector in autonomic motor pathways

2 neurons: preganglionic and postganglionic

Why is the adrenal medulla described as a modified sympathetic ganglion?

because its postganglionic cells release EPI and NOEPI into the blood instead of sending axons to a target

what does stimulation of the adrenal medulla release?

85% Epi and 15% Noepi into the bloodstream

How does parasympathetic stimulation change pupil diameter?

parasympathetic stimulation constricts the pupil - miosis

Which iris muscle causes constriction of the pupil?

the contraction of the sphincter pupillae muscle

what NT is released by sympathetic preganglionic neurons

ACh

what NT is released by sympathetic postganglionic neurons

Norepinephrine
*except sweat glands - sympathetic postganglionic neurons that innervate sweat glands and blood vessels in skeletal muscles release ACh

what makes a nerve fiber adrenergic

releases norepinephrine

what makes a nerve fiber cholinergic

releases ACh

Adrenaline is also known as

Epinephrine

how does parasympathetic stimulation affect digestive activity and intestinal motility

increases digestive activity, increases intestinal motility

which motor division normally reaches its effector through peripheral ganglion?

autonomic

Would isolated damage to autonomic motor nerves directly produce skeletal muscle paralysis or loss of skeletal muscle tone?

No, autonomic motor nerves do not directly control skeletal muscle. Skeletal muscle is innervated by somatic motor neurons; therefore, isolated damage to autonomic motor nerves would primarily interfere with functions involving: smooth muscle, cardiac muscle, glands

where in the CNS does the autonomic preganglionic neuron cell bodies reside?

Sympathetic preganglionic neurons - thoracic and lumbar spinal cord - thoracolumbar

Parasympathetic preganglionic neurons - brainstem and sacral - craniosacral

Where do parasympathetic preganglionic neurons originate, and where do they synapse?

• cranial/brainstem: midbrain, medulla, pons

• Sacral S2-S4

• synapse on postganglionic in terminal ganglia located next to or within target organ

Which cranial nerves provide parasympathetic input to salivary glands, and which glands are associated with each?

CN VII — Facial nerve

• Submandibular gland (under the jaw, produces saliva)

• Sublingual gland (under the tongue, produces saliva)

CN IX — Glossopharyngeal nerve

• Parotid gland (located in front of and slightly below the ears, produces saliva)

Describe the usual preganglionic length, ganglion location, and neurotransmitters of the parasympathetic division.

Preganglionic are long, ganglion located near or inside the target organ, releases ACh

how does the iris demonstrates dual autonomic innervation

Receives input from both sympathetic and parasympathetic divisions that have opposing effects on pupil diameter

• dilator pupillae → dilate (mydriasis)

• sphincter pupillae → constricts (miosis)

What role does the hypothalamus play in autonomic regulation, and how does it relate to autonomic centers in the medulla?

Hypothalamus coordinates autonomic response involving homeostasis, it regulates the medulla

autonomic innervation of the urinary bladder

receives both sympathetic and parasympathetic innervation (storage of urine and urination)

autonomic innervation of the adrenal medulla

receives sympathetic preganglionic input and releases EPI and NOEPI

autonomic innervation of the arrector pili muscles

Receive primarily sympathetic innervation, contractions causes production of goosebumps/piloerection.

autonomic innervation of the blood vessels

Receive primarily sympathetic innervation.

Which postganglionic autonomic neurons release acetylcholine

parasympathetic

Chemoreceptors

detects chemical stimuli - taste and smell and internal physiological regulation

nociceptors

detect damaging or tissue injuring stimuli — pain

How do proprioceptors help you determine the position of a limb without looking at it?

provide information about muscle length, muscle tension, joint position, and movement of limbs

Phasic receptors

• responds strongly when a stimulus first occurs

• rapidly adapting

• detects change in a stimuli

Tonic receptors

• slow adapting

• monitors continued conditions

what type of cell detects taste?

gustatory cells

how does taste cells communicate with a sensory neuron

with NT and sensory neuron carries the taste info to the brain

Utricle

horizontal linear acceleration; forward and back, side to side

Saccule

vertical linear acceleration; up and down

semicircular canals

angular/rotational acceleration

How does the stapedius muscle affect sound transmission?

• reduces the movement of the stapes

• decreases transmission of vibrations into the inner ear

• protects inner ear from loud sounds

what results from loss of stapedius muscle function?

• stapes move more freely

• more sound transmitted into the ear

• becomes more vulnerable to damage from loud sounds

Superior colliculi

visual processing; coordinates eye and head movement, orienting toward visual stimuli

Inferior colliculus

auditory processing

How does the lens receive nourishment?

through diffusion of nutrients and oxygen from the aqueous humor

cutaneous receptors

sensory receptors on the skin, detects touch, pressure, temperature, pain, classified as exteroceptors

Interoceptors

detects information from inside the body, particular visceral organs

proprioceptors

detects body position through muscle length, muscle tension, and joint movement

What are the major cutaneous touch and pressure receptors

meissner corpuscles, merkel disc, pacinian corpuscles, ruffini endings, free nerve endings

Meissner corpuscles

• changes in texture; slow vibration

merkel discs

• sustained touch and pressure

Free nerve endings

• light touch

• cold, hot, pain

Ruffini corpuscles

sustained pressure

pacinian corpuscles

deep pressure, fast vibrations

Golgi tendon organ

• not a cutaneous receptor, it is a proprioceptor located in tendon

• detects muscle tension

cutaneous receptors

detects stimuli at the skin

2 point discrimination

the ability to distinguish two nearby points of contact as two separate stimuli.

receptor density

how many sensory receptors are packed into a certain area of skin

receptive field

area of skin monitored by one sensory neuron/receptor pathway

lateral inhibiton

occurs when strongly stimulated sensory neurons inhibit the activity of neighboring sensory pathways, creates sharper localization

Which cranial nerve carries taste from the anterior tongue

CN VII - facial nerve

Which special sense has prominent direct connections with limbic structures, and how does that help explain its association with emotion and memory?

smell - olfaction; has connections with areas involved in emotion and memory

vestibular apparatus

• balance and equilibrium

• utricle, saccule, and 3 semicircular canals

cochlea

• responsible for hearing

• detects sound vibration

What happens to a vestibular hair cell when its stereocilia bend toward its kinocilium?

1. K+ channels open

2. Hair cells depolarizes

3. Hair cells release glutamate

4. sensory neuron receives glutamate

5. brain interprets it as sound

What physical property of sound is measured in hertz?

frequency (cycles per sec)

How is pitch related to frequency?

high frequency → higher pitch

lower frequency → lower pitch

Auditory pathway from inner ear to cerebral cortex

1. cochlea

2. vestibulocochlear nerve (CN VIII)

3. medulla oblongata

4. inferior colliculus of the midbrain

5. thalamus

6. auditory cortex of the temporal lobe

presbycusis

age related decline in hearing

presbyopia

age related decine in vision/focusing ability

Endocrine glands

• does not use ducts

• releases hormones directly into the interstitial fluid which then enters the bloodstream

Exocrine glands

• release their secretions into ducts

• ducts care the secretion to a body surface or into a body cavity

Why is the pancreas considered a gland with both endocrine and exocrine functions?

it performs both endo (beta and alpha cells) and exocrine (secretes digestive enzymes that travels through pancreatic ducts into the small intestine) function

Why are ordinary polypeptide and glycoprotein hormones generally ineffective when swallowed?

Theses proteins get broken down by the substances in the stomach and GI tract which makes the protein hormone ineffective

How are lipophilic hormones transported in blood, and what must happen before they enter a target cell?

they must bind to a carrier protein, which they then dissociate from when they reach the target cell

• they are able to diffuse through the phospholipid bilayer but cannot move through the blood plasma

Where are posterior pituitary hormones synthesized, and what does the posterior pituitary do with them?

Posterior pituitary hormones (ADH and oxytocin) are synthesized in the hypothalamus. The posterior pituitary only stores and releases hormones, they do not make hormones.

Predict how inhibiting luteinizing hormone secretion would affect testosterone production.

LH stimulates testosterone production; so dec. in LH = dec. in testosterone production

Trace how inadequate dietary iodine affects thyroid hormone levels and TSH secretion.

Iodine is required to make thyroid hormones T3 and T4

• if there is a deficiency in Iodine, the thyroid cannot produce enough T3 and T4 → inc. TSH = inc. thyroid stimulating → potentially a goiter

Where are insulin-producing beta cells located, and how can loss of their function affect blood glucose?

located in the pancreatic islets of the pancreas

• loss of beta cell function → dec. in insulin → dec. in glucose uptake → inc. in blood glucose → diabetes

hydrophilic passage through a plasma membrane

binds to receptors on the cell membrane

hydrophoic passage through a plasma membrane

can interact easily with lipids and pass through the bilayer

lipophilic passage through a plasma membrane

diffuses through the bilayer and bind to intracellular receptors

Which pituitary region secretes ACTH

anterior pituitary

what is the relationship of ACTH to cortisol secretion?

ACTH acts on the adrenal cortex, stimulating secretion of cortisol, a glucocorticoid

How would increased somatostatin affect growth hormone secretion and growth?

somatostatin inhibits GH secretion; inc. somatostatin = dec. GH = dec. growth

What does ADH do to renal water handling, and what happens to urine volume when its effect increases?

conserve water, ADH inc. water retention and dec. urine volume

Effect of growth hormone excess before the growth plates close

excess GH → gigantism; excessive growth of long bones and abnormally increased height

Effect of growth hormone excess after the growth plates close

excess GH → acromegaly; enlarged hands, feet, jaw, facial bones

Name the three functional hormone categories produced by the adrenal cortex

mineralocorticoid, glucocorticoid, sex steroids

Mineralocorticoid

Regulate:

• Electrolyte balance

• Na⁺ retention

• Water balance

• Blood pressure

**Example:

• Aldosterone

Produced primarily by the zona glomerulosa.

Glucocorticoids

Important for:

• Metabolism

• Stress responses

• Increasing blood glucose

• Modulating immune/inflammatory responses

**Example:

• Cortisol

• hydrocortisone

Produced primarily by the zona fasciculata.

Sex steroids

weak androgens

• DHEA

• Produced primarily by the zona reticularis.

How does aldosterone help increase extracellular fluid volume and blood pressure?

acts on the kidney

• inc. Na reabsorption — water follows

• Inc. K secretion

inc. blood volume and inc. blood pressure

Addison Disease

• inadequate secretion of adrenal glucocorticoid and mineralocorticoids

• low cortisol

• low aldosterone

• low androgens

• hyperpigmentation

• adrenal hormones are low

• Results in hypoglycemia, Na and K imbalance

• dehydration, hypotension, weight loss, and generalized weakness

If beta cells are destroyed…

insulin production decreases, decreases glucose uptake, and increased blood glucose → diabetes mellitus

Epimysium

surrounds the entire skeletal muscle

perimysium

surrounds a fascicle (bundle of muscle fiber)

endomysium

surrounds each individual muscle fiber

Where are Z discs and M lines located relative to the I and A bands?

Z discs marks the boundaries of a sarcomere, located at the center of each I band, M line is located in the center of the A band

During muscle contraction, what happens to the A band, I band, H zone, and filament lengths

• A → stays the same length

• I → shortens

• H → shortens and may disappear

• filaments → stay the same length

How do the basal nuclei influence skeletal muscle activity?

• Help initiate and regulate voluntary movement

• Help control the force and pattern of movement

• Help suppress unwanted movements.

• Damage to basal nuclei results in increased muscle tone.

How do the cerebellum influence skeletal muscle activity?

• Coordinates movement.

• Helps maintain balance and posture.

• Helps regulate timing, precision, and accuracy.

• Compares intended movement with actual movement and helps correct errors.