A&P Test #4

Pancreas characteristics

- Elongated organ between duodenum and spleen - Posterior to the stomach, Performs exocrine and endocrine activities - Mostly composed of groups of cells, pancreatic acini - produce alkaline pancreatic secretion , secreted through pancreatic ducts into small intestine

Parathyroid glands

- Four nodules on posterior thyroid gland - Two different cell types: - chief cells - source of parathyroid hormone - released in response to decreased blood calcium levels - return blood calcium to normal levels - oxphil cells - function unknown

Lowering High Blood Glucose Levels with Insulin

- Insulin released from pancreas following food intake - Glucose levels detected by chemoreceptors - Target cells bound by insulin - activates second messengers in target cells - Release of insulin - results in decrease in all nutrients in blood - increase in synthesis of storage forms of molecules - decrease of alternative nutrients - cells more likely to use available glucose - decreases with decreased glucose levels

Hormones stored in posterior pituitary

- Oxytocin - Antidiuretic hormone (ADH)

Anatomy of the Adrenal Glands

- Paired, pyramid-shaped endocrine glands - Anchored on superior surface of each kidney - Retroperitoneal, embedded within fat and fascia - Supplied by suprarenal arteries branching from abdominal arteries - Two regions - adrenal medulla and adrenal cortexAction of Cortisol

Action of Thyroid Hormone

- Stimulates other target cells to meet additional ATP requirements - Increased respiration rate to meet additional oxygen demand - Increased heart rate and force of contraction - increases blood flow to tissues - Adjusts basal metabolic rate of many cells - Stimulates synthesis of sodium-potassium pumps in nervous tissue - Action generates heat • rise in temperature referred to as calorigenic effect - Stimulates increased amino acid and glucose uptake - Increases cellular respiration enzymes within mitochondria

Hormones of the Anterior Pituitary

- Thyroid-stimulating hormone (TSH) - Prolactin - Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) - Adrenocorticotropic hormone (ACTH) - Growth hormone - Melanocyte-stimulating hormone (MSH)

Hypothalamus hormones

- Thyrotropin-releasing hormone - Prolactin-releasing hormone - Gonadotropin-releasing hormone - Corticotropin-releasing hormone - Growth hormone-releasing hormone

Diabetes mellitus

- inadequate uptake of glucose from blood - with chronically elevated glucose, blood vessels damaged - leading cause of retinal blindness, kidney failure, and nontraumatic amputations in the United States - associated with increased heart disease and stroke

What are the three types of unencapsulated tactile receptors?

1) free nerve endings (detect pain, temperature, light touch and pressure) 2) root hair plexuses (signal initiated by hair movement) 3) tactile discs (tonic receptors for fine touch)

What is the correct order through which sound travels in the inner ear? 1. endolymph of cochlear duct 2. round window 3. perilymph of scala vestibule 4. vestibular membrane 5. oval window 6. perilymph of scala tympani 7. basilar membrane

5, 3, 4, 1, 7, 6, 2

Which of the following statements about thyroxine is true? It is water-insoluble. It is lipophilic. It can pass through the cell membrane. All of these choices are correct.

All of these choices are correct.

First, match the taste receptor to the proper cranial nerve name, and then choose the appropriate cranial nerve number. Anterior two-thirds of the tongue Posterior one-third of the tongue and the superior pharynx Epiglottis

Anterior two-thirds of the tongue: Facial nerve VII Posterior one-third of the tongue and the superior pharynx Glossopharyngeal nerve IX Epiglottis Vagus nerve X

Which pancreatic islet cell type is correctly matched with its product? Beta cells : insulin Cells : somatostatin Alpha cells : insulin Delta cells : glucagon

Beta cells : insulin

Stimulus

Change in a regulated variable; event that provokes a cellular response.

Pineal gland hormones

Composed primarily of pinealocytes secreting melatonin makes us drowsy

Sensation

Conscious awareness of sensory information Only stimulus that reaches cerebral cortex

Unencapsulated tactile receptors

Dendritic ends of sensory neurons with no protective coat

True/False: As the eye adjusts to focus on a near object, the cornea must change shape because the lens is unable to.

False

True/False: Each of the body's blood-borne hormones comes from the major endocrine glands, namely, the pineal, pituitary, thyroid, parathyroid, or adrenal glands.

False

True/False: Gustatory receptors are classified as mechanoreceptors because food molecules must be dissolved in saliva before they can be tasted.

False

True/False: The reason we can detect so many different odors is that each olfactory neuron is slightly different from the others, allowing for a wide range of odor sensations.

False

True/False: Although hormones influence activity in the neural and reproductive systems, they do not influence the digestive system.

False

True/False: Olfactory cilia contain axon terminals?

False

True/False: Olfactory receptors bind to and actively take in odorants.

False

True/False: Steroids, peptides, and nucleic acids are the three classes of hormones.

False

True/False: T3 and T4 are secreted by the parafollicular cells.

False

True/False: The change in ACTH levels in response to stress causes a decrease in glucocorticoid secretion from the adrenal cortex

False

True/False: The function of each of the regulatory hormones of the hypothalamus is to trigger the release of a tropic hormone from the pituitary.

False

True/False: The posterior pituitary produces both inhibiting and releasing hormones.

False

True/False: The reaction time for endocrine effects is generally measured in milliseconds.

False

True/False: The pineal gland secretes the hormone melanin.

False Melanin is a pigment that is produced by cells known as melanocytes in the skin of most animals. The production of melanin is affected by UV exposure, genetic make-up, size of melanocytes, and disease conditions.

True/False Lipid-soluble hormones are those such as insulin, glucagon, ADH, and oxytocin.

False.

True/False: Accommodation is a result of parasympathetic stimulation from the optic nerve.

False. It is due to the sympathetic stimulation

True/False: Structurally, olfactory neurons are unipolar neurons

False. They are bipolar

True/False: High-pitched sounds produce a peak displacement of the basilar membrane near the apex of the cochlea.

False: High-pitched sounds produce a peak displacement of the basilar membrane near the base of the cochlea.

True/False: The ability to not notice the smell of fish from the previous day is due to tonic receptors.

False: Sensory adaptation is due to phasic receptors that give a burst of firing when the stimulus starts and then again when it ends.

True/False: A receptor is an axon that carries sensory impulses to the spinal cord's dorsal horn of gray matter.

False: A receptor is any structure specialized to detect a stimulus not send an impulse.

True/False: Light causes Na+ channels in rods to close, causing hyperpolarization, and the release of inhibitory neurotransmitter to bipolar cells.

False: Light causes Na+ channels in rods to close, causing hyperpolarization, and stops the release of inhibitory neurotransmitter to bipolar cells.

True/False: Rods and cones face the light coming into the eye.

False: Rods and cones actually face away from the incoming light. They face the back of the retina toward the pigmented layer and choroid. Light travels through the ganglion cells, and bipolar cells, before reaching the photoreceptors.

True/False: Our brain perceives different colors because each cone responds to a different wavelength on the visual spectrum.

False: There are only three different types of cones. Each cone responds to a range of wavelength. The combination of stimulation to different cones results in the perception of different colors.

Which of the following hormones primarily affects the reproductive organs? Follicle-stimulating hormone Adrenocorticotropic hormone Prolactin-releasing factor Thyrotropin Growth hormone

Follicle-stimulating hormone

The binding of epinephrine to its receptor activates ________, which in turn activates ________.

G-protein; adenylyl cyclase

The pancreas has pancreatic islets composed of primarily alpha and beta cells. Alpha cells secrete?

Glucagon

What neurotransmitter is released from depolarized hair cells to stimulate fibers of the vestibulocochlear nerve?

Glutamate

Thyroid hormone stimulates the anterior pituitary to release

Growth hormone

The messenger in the lipid soluble messenger system is?

Hydrophobic

Decide if these retinal events occur in the dark or in the light. Glutamate inhibits the bipolar cells that synapse with the rods.

In the dark

Decide if these retinal events occur in the dark or in the light. Rods continuously release the neurotransmitter glutamate.

In the dark

Decide if these retinal events occur in the dark or in the light. The bipolar cells do not stimulate the ganglion cells

In the dark

Decide if these retinal events occur in the dark or in the light. Action potentials are transmitted out of the optic nerve.

In the light

Decide if these retinal events occur in the dark or in the light. Activated rhodopsin inhibits the production of glutamate by rods.

In the light

Decide if these retinal events occur in the dark or in the light. The bipolar cells stimulate the ganglion cells.

In the light

Hyperglycemia (high blood glucose levels) would cause the pancreas to _________ insulin secretion, and hypoglycemia (low blood glucose levels) would cause the pancreas to _________ insulin secretion.

Increase/Decrease

hypothalamus

Influences or controls many endocrine glands Has direct control over hormone release from pituitary gland Has indirect control over hormone release from: thyroid and adrenal glands liver, testes, and ovaries

Receptive field

Inverse relationship between field size and ability to identify location If field small, precise location determined easily

Oxytocin

It can cause or strengthen labor contractions during childbirth, and control bleeding after childbirth. It can also be used to induce abortion.

What is the role of thyroxine?

It's a hormone produced by the thyroid gland. Thyroxine is important in controlling both development and maturation. It also controls metabolism in adult organisms.

What ion is responsible for depolarization of hair cells of the spiral organ?

K+

Pituitary gland

Lies inferior to the hypothalamus Approximately the size of a pea Housed within sella turcica of sphenoid bone Connected to hypothalamus by thin stalk, infundibulum Partitioned into anterior and posterior pituitary

_____________ hormones bind to nuclear receptors, usually found in the nucleus; _____________ hormones bind to membrane-bound receptors.

Lipid-soluble; water-soluble

What stimulates the secretion of parathyroid hormone from the parathyroid gland?

Low blood calcium

What are the main functions of the endocrine system?

Maintaining homeostasis of blood composition and volume. Controlling reproductive activities Regulating development, growth, and metabolism Controlling digestive processes

Tactile receptors

Most numerous type of receptor Mechanoreceptors located in dermis and subcutaneous layer Respond to touch, pressure, vibration

Which of the following has both endocrine and exocrine functions? Pancreas Anterior pituitary Liver Thyroid gland Pineal gland

Pancreas

The parathyroid glands are located on the ____________ surface of the thyroid gland.

Posterior

Antidiuretic hormone (ADH) is released by the?

Posterior pituitary

Sensory neurons(Gustatory pathways)

Project first to medulla to synapse

Endocrine system

Regulates and controls many metabolic processes Helps maintain body homeostasis -ex) maintaining blood glucose levels during erratic food intake

Phantom Pain

Stimulation of sensory neuron pathway on remaining portion Cell body still alive Pain sometimes quite severe Sensation associated with removed body part

Visceral pain is usually referred along which nerve pathways?

Sympathetic nerve pathways (sometimes parasympathetic)

What is the basic composition of a taste bud? Which papillae have taste buds?

Taste buds are composed of gustatory cells, supporting cells, and basal cells. They are found in fungiform, vallate (most prevalently), and foliate papillae.

Which nerve fibers cross in the optic chiasma?

The axons of ganglion cells from the nasal halves of both retinas cross in the optic chiasma. The left visual fields from both eyes project to the left lateral geniculate body of the thalamus. The right visual fields from both eyes project to the right lateral geniculate body of the thalamus.

Refraction

The bending of light.

Convex

The lens is thicker in the center than on the sides and the light rays converge.

Concave

The lens thinner in the center than on the sides and the light rays diverge.

The _______ secretes triiodothyronine.

Thyroid

True/False: Receptors contain modality-gated channels within their plasma membranes.

True

True/False: Visual pathways include axons that project from the optic tracts to the superior colliculi.

True

True/False: Parathyroid hormone functions to raise blood calcium levels.

True

True/False: The thymus gland secretes erythropoietin in response to low blood oxygen.

True

True/False: A rise in glucocorticoids can promote insulin resistance.

True

True/False: All hormone secretion is under the direct control of the hypothalamus.

True

True/False: An increase in stress causes an increase in ACTH from the anterior pituitary.

True

True/False: Axons from the vestibular nerve project to each of the cranial nuclei that control the extrinsic eye muscles.

True

True/False: Glucocorticoids suppress the immune system.

True

True/False: Growth hormone releasing hormone (GHRH) is one of the regulatory hormones released by the hypothalamus that acts on the pituitary.

True

True/False: Increasing levels of cortisol inhibit the release of corticotropin-releasing hormone (CRH).

True

True/False: Olfactory receptor cells are modified bipolar neurons that bear olfactory hairs.

True

True/False: Olfactory receptors utilize G-proteins to open ion channels.

True

True/False: Stimulation of olfactory receptor cells involves activation of G-protein molecules inside them.

True

True/False: Suspensory ligaments function to change the shape of the lens within the eye.

True

True/False: T3 and T4 are secreted by thyroid follicles.

True

True/False: T3 and T4 are stored in the thyroid follicles as part of thyroglobulin.

True

True/False: The hormones secreted by the adrenal medulla are amines.

True

True/False: The otolithic membrane functions in hearing and in maintaining equilibrium.

True

True/False: The pancreas has both endocrine and exocrine functions.

True

True/False: The posterior pituitary does not produce its own hormones but stores hormones produced by the hypothalamus.

True

True/False: The semicircular ducts are part of the membranous labyrinth.

True

True/False: Thyroid-stimulating hormone (TSH) stimulates T3 and T4 synthesis and secretion.

True

True/False:The retina is composed of two layers: an inner pigmented layer and an outer neural layer.

True

True/False:The superior colliculi and pretectal nuclei function to direct reflexive responses to visual stimuli.

True

True/False: When a generator (receptor) potential reaches threshold, an action potential will be produced.

True: An action potential will be produced once the receptor potential has reached threshold.

True/False: Walking into a room and recognizing the smell of a favorite dish is an example of a sensation.

True: A sensation is the conscious awareness of incoming sensory information, as in recognition of a face.

The hypothalamo-hypophyseal portal system connects the hypothalamus to the

adenohypophysis.

As a result of the general stress response, blood concentrations of epinephrine rise and cortisol fall. fall and cortisol rise. and cortisol rise. and cortisol fall.

and cortisol rise.

Target cells for releasing hormones are in the?

anterior pituitary gland.

Sensory receptors

are components of the nervous system that provide us with information about both our external and internal environment.

Epinephrine binds to

beta-adrenergic receptors on the cell membrane of liver cells.

Perilymph is contained within the

bony and membranous labyrinths.

Outer hair cells, near the center of the basilar membrane, will

both magnify vibrations of soft sounds and sharpen pitch perception.

Aldosterone promotes the homeostasis of ions by causing the kidneys to?

conserve sodium and excrete potassium. aldosterone is produced in the zona glomerulosa of the adrenal cortex

Proprioceptors

detect body and limb movements

Baroreceptors

detect changes in stretch or distension. Baroreceptors are a type of mechanoreceptor that are found in the blood vessels.

Chemoreceptors

detect chemicals dissolved in fluids

Phasic receptors

detect new stimulus or change in stimulus sensitivity decreases over time e.g., tactile receptors of skin

Exteroceptors

detect stimuli from external environment

Interoceptors

detect stimuli of internal organs

Transducers

device or organ designed to convert energy from one form to another.

General sense receptors

distributed throughout the body located in the skin and internal organs typically simple in structure

Filiform papillae

do not house taste buds. Letter A on this diagram

Local hormones are a large group of signaling molecules of which the primary type are called?

eicosanoids.

Encapsulated tactile receptors

end bulbs - located in -skin dermis -mucous membranes of oral cavity, nasal cavity -vagina, anal canal -detect light pressure stimuli and low-frequency vibration

The papillae on the tongue that do not contain any taste buds are the ________ papillae.

filiform

Tactile corpuscles

found in -dermal papillae of skin -especially lips, palms, eyelids, nipples, genitals

Bulbous corpuscles

found in -dermis and subcutaneous layer -joint capsules -detect continuous deep pressure and distortion in the skin

lamellated corpuscles

found in -reticular layer of dermis -subcutaneous tissue of palms, soles, breasts, external genitalia -synovial membranes of joints -walls of some organs

As the number of cycles per second increases, the sound we perceive

gets higher

What are examples of hormones that function through activation of adenylate cyclase?

glucagon, antidiuretic hormone, epinephrine, thyroid-stimulating hormone, and follicle-stimulating hormone.

The sensory receptors of the inner ear for equilibrium are

hair cells

When you travel in an elevator, the ___ sense when the elevator is moving.

hair cells of the otolithic membrane of the macula sacculi

Taste buds

have appearance of an onion contain numerous taste receptors, gustatory cells have 7 to 10 day life span

Antidiuretic hormone (ADH)

helps your kidneys manage the amount of water in your body.

somatic sensory receptors

housed within the skin, joints, muscles, tendons detect pressure, vibration, pain, stretch

The pituitary gland is located in the

hypophyseal fossa.

Growth hormone-releasing hormone

increases secretion of growth hormone

A part of the auditory pathway responsible for auditory reflexes is the

inferior colliculus.

The thyroid gland is located ____________ to the larynx and is composed of two lobes connected by a narrow band of tissue called the ___________.

inferior; isthmus

The endocrine portion of the pancreas produces?

insulin and glucagon.

Vallate papillae

least numerous, largest papillae, arranged in inverted V on posterior dorsal tongue, each surrounded by deep, narrow depression, most taste buds housed here Letter B on this figure

Photoreceptors

located in the eye and detect light signals.

visceral sensory receptors

located in walls of viscera respond to temperature, chemicals, stretch, pain

Special senses receptors

located within head specialized, complex sense organs

Target organs regulate the pituitary through feedback loops. Most often, this takes the form of? positive feedback. direct nervous stimulation. negative feedback inhibition. All of the choices are correct. Hint: An overactive thyroid gland often causes a decrease in TSH production.

negative feedback inhibition.

ADH and oxytocin are secreted by?

neurosecretory cells.

Foliate papillae

not well developed in humans, extend as ridges on posterior lateral tongue, house only a few taste buds through early childhood Letter D on this figure

Fungiform papillae

on tip and sides of tongue, contain a few taste buds Letter C on this diagram

The pancreas is mostly composed of groups of cells called

pancreatic acini.

After the thalamus, auditory nerve signals reach the

primary auditory cortex

Tonic receptors

respond continuously to stimuli at constant rate e.g., balance receptors in inner ear

Thermoreceptors

respond to changes in temperature

Nocioceptors

respond to painful stimuli

Receptors

respond to stimuli

Mechanoreceptors

respond to touch, pressure, vibration, and stretch that occur in the plasma membrane

Odorant-binding proteins

soluble proteins within mucus

Receptors on the tongue are classified into what three receptor criteria?

special senses, chemoreceptors, and exteroceptor

Tropic hormones

stimulate certain endocrine glands to secrete hormones.

The thyroid gland secretes large amounts of?

tetraiodothyronine and small amounts of triiodothyronine.

After turning on a bright light in a previously dark room, it is difficult to see for a brief time. This is because?

the photoreceptors are photobleached.

Glucocorticoids

• Cortisol and corticosterone most common • increase nutrient levels in blood • attempt to resist stress and repair injured tissue

Follicle-stimulating hormone (FSH) and luteinizing hormone (LH)

• collectively called gonadotropins • regulate hormone synthesis by the gonads & production and maturation of gametes

Hypoglycemia

• glucose levels below 60 mg/DL • numerous causes: - insulin overdose, prolonged exercise, alcohol use, liver or kidney dysfunction - deficiency of glucocorticoids or growth hormone, genetics • symptoms of hunger, dizziness, confusion, sweating, and sleepiness • glucagon given if individual unconscious and unable to eat

Corticotropin-releasing hormone

• increases secretion of adrenocorticotropic hormone

Gonadotropin-releasing hormone

• increases secretion of follicle-stimulating hormone and luteinizing hormone

Prolactin-releasing hormone

• increases secretion of prolactin Prolactin's primary role is to help initiate and maintain breast milk production in pregnant and nursing women.

Thyrotropin-releasing hormone

• increases secretion of thyroid-stimulating hormone

Pancreatic endocrine function

• maintaining normal blood glucose • Normal range 70 to 110 mg of glucose/deciliter • Chronically high levels damaging to blood vessels and kidneys • Low levels resulting in lethargy, mental and physical impairment, and death (if too low).

Prolactin

• regulates mammary growth and breast milk production

Thyroid-stimulating hormone (TSH)

• regulates release of thyroid hormone from thyroid gland

Adrenocorticotropic hormone (ACTH)

• stimulates adrenal cortex to produce and secrete glucocorticoids

Growth hormone

• stimulates cell growth and cell division • affects most body cells, particularly skeletal and muscular system

Melanocyte-stimulating hormone (MSH)

• stimulates rate of melanin synthesis by melanocytes in skin