Physiology Exam Review #3 Flashcards
What are the general senses of touch (tactile)?
- Temperature (thermoreceptors)
- Pressure (mechanoreceptors)
- Nociceptors (mechanoreceptors) (pain)
What are the special senses?
- Smell (chemoreceptors)
- Taste (chemoreceptors)
- Sight (photoreceptors)
- Hearing (mechanoreceptors)
- Equilibrium (mechanoreceptors)
A structure specialized to detect a stimulus
Sensory receptor
Nerve tissue surrounded by other tissues that enhance response to a certain type of stimulus
True sense organs
Accessory tissues of true sense organs
Epithelium, muscle, or connective tissues
A subjective awareness of the stimulus
Sensation
Sense chemicals in the environment (taste, smell), or blood
Chemoreceptors
Sense light
Photoreceptors
Respond to cold or heat
Thermoreceptors
Stimulated by mechanical deformation of the receptor (touching, hearing)
Mechanoreceptors
Pain receptors that depolarize when tissues are damaged
Nociceptors
What are the main neurotransmitters for nociceptors
Glutamate and substance P
Perception of pain can be enhanced by..
Emotions, concepts, and expectations
Found in the muscles, tendons, and joints. Provide a sense of body position and allows fine muscle control
Include muscle spindles (detect stretch), Golgi tendon organs (detect tension) and joint receptors
Proprioceptors
Touch, pressure, heat, cold, and pain
Cutaneous (skin) receptors
Respond to stimuli from outside of the body; includes cutaneous receptors and special senses
Exteroceptors
Respond to internal stimuli; found in organs; include mechanoreceptors and chemoreceptors; monitor blood pressure, pH, and oxygen concentrations
Interceptors
Respond with a burst of activity when stimulus is first applied but quickly adapt to the stimulus by decreasing response; adapts rapidly
Alerts us to changes in the environment
Phasic
Maintains a high firing rate as long as the stimulus is applied; adapts slowly
Tonic
Pain from the skin, muscles, and joints
Somatic pain
Pain from the viscera (stretch, chemical irritants, or ischemia of viscera
Visceral pain
Chemical released from tissues that stimulate pain fibers; most potent pain stimulus known
Bradykinin
Which other chemicals stimulate nociceptors for pain?
Histamine, prostaglandin, and serotonin
Pain in viscera that is often mistakenly thought to come from the skin or other superficial sites
Referred pain
What is referred pain the result of?
Convergence of neural pathways in CNS
Term for pain relieving mechanisms within the CNS
Analgesic
Internally produced opium-like substances
Endogenous opioids
Two analgesic oligopeptides with 200 times the potency of morphine
Enkephalins
Larger analgesic neuropeptides discovered later
Endorphins and dynorphins
What systems release the modulations of pain?
CNS, pituitary gland, digestive tract, and other organs
Which senses use chemoreceptors?
Taste and smell
How many receptors do taste have?
5 - including umami
Another term for taste
Gustation
What are the receptors of taste called?
Taste buds
Epithelial cells that are not neurons but become depolarized when stimulated, produce action potentials, and release neurotransmitters to stimulate the sensory neurons
Neuroepithelial cells
Where are taste buds located?
Papillae
Which papillae is located on the anterior surface and information travels via the facial nerve (VII)
Fungiform
Which papillae is located on the posterior surface and information travels via the glossopharyngeal nerve (IX)
Circumvallate
Which papillae is located on the sides of the tongue and information travels via the glossopharyngeal nerve (IX)
Foliate
What is the taste pathway
Facial and glossopharyngeal nerves ->
Medulla oblongata ->
Thalamus ->
Primary gustatory cortex of insula, somatosensory cortex of parietal lobe, and prefrontal cortex
What kind of cells are the taste cells
Specialized epithelial cells
What is taste influenced by
The temperature and texture of the substance, the concentration of the chemical, and the stimulation of olfactory receptors
What are the five primary sensations (taste)
Salty, sweet, sour, bitter, umami
Taste sensation produced by metal ions (sodium and potassium)
Salty
Taste sensation associated with carbohydrates and sugars
Sweet
Taste sensation associated with acids, such as in citrus fruits
Sour
Taste sensation associated with some spoiled foods and alkaloids such as caffeine, quinine, morphine, and nicotine
Bitter
Taste sensation associated with meaty or savory flavors associated with amino acids, broths, MSG
Umami
Another term for sense of smell
Olfaction
Bipolar neurons with one dendrite projecting into the nasal cavity that ends in a ciliated knob
Olfactory receptors
What binds to odorant molecules
Proteins in the cilia
How many genes code for different olfactory receptors
380 genes code for 380 different olfactory receptors
Which system is also involved in processing of smell
The limbic system
A response to vibrating air molecules
Hearing
The sense of motion, body orientation and balance
Equilibrium
Where does hearing and equilibrium reside
The inner ear
Provides a sense of balance
Equilibrium - Vestibular Apparatus
Where are the otolith organs (Utricle and Saccule) and Semicircular canals located
In the Vestibular Apparatus
Detect linear acceleration
Otolith organs (Utricle and Saccule)
Detect rotational acceleration
Semicircular canals
Modified epithelial cells with 20 to 50 hairlike extensions called stereocilia (not true cilia) and one kinocilium (true cilim)
Vestibular hair cells
Modified microvilli and are arranged in rows of increasing height
Stereocilia
Provide information about linear acceleration and movement
Utricle: horizontal
Saccule: vertical
What are stereocilia embedded in
A gelatinous otolithic membrane - contains carbonate called otoliths (ear stones)
Project along three planes to detect rotation
Semicircular canals
What does each semicircular canal contain
A semicircular duct filled with endolymph
What is at the base of each semicircular duct
An enlarged area called the ampulla
Alternating zones of high and low pressure traveling in a medium, usually air or water
Sound waves
What are sound waves characterized by
Frequency (measured in hertz), Intensity or loudness (measured in decibels)
Sound waves are funneled by the pinna (or auricle) into the external auditory meatus, which channels them to the tympanic membrane (eardrum)
Outer ear
Cavity between the tympanic membrane and cochlea
Middle ear
Middle ear contains three bones called..
Auditory ossicles
Which auditory ossicle is connected to the tympanic membrane and incus
Malleus
Which auditory ossicle is connected to the Malleus and the Stapes
Incus
Which auditory ossicle is connected to the Incus and the Oval Window and vibrates in response to vibrations of the tympanic membrane
Stapes
What causes vibration of basilar membrane under hair cells
Vibration of ossicles
What is the hearing part of the ear
The cochlea
What is the upper chamber of the cochlea
A portion of the bony labyrinth called the scala vestibuli
What is the lower bony chamber of the cochlea
Scala tympani
What are both chambers of the cochlea filled with
Perilymph
What is the gel-like membrane that is capable of bending hair cells
Organ of Corti
Transform sound waves in cochlear fluid into nerve impulses
Inner hair cells
What percentage of sensory receptors are in the eye
70 percent
Where does vision come from
Light energy transduced into nerve impulses
What is the general pathway of light through the eye
Light passes through the cornea and into the anterior chamber
Then, passes through the pupil
Then, passes through the lens, which can change shape to focus image
Then passes through the posterior chamber and the vitreous body
Finally, hits the retina, where photoreceptors are found and then absorbed by the pigmented choroid layer
Composed of layers of living cells that are normally completely clear and requires its own microcirculatory system to sustain its cells
The lens
The lens is avascular meaning..
It has no blood supply
Cell metabolism is very low and is anaerobic in which part of the eye
The lens
Transparent and composed predominantly of cells called “mature fibers” that lack organelles
The lens
What are the lens attached to
Ciliary bodies
The minimum distance from the eyes that an object can be brought into focus
Near point of vision
Loss of accommodation with age - reduced flexibility of the lens, forward movement of zonular fiber attachment, and lens cannot thicken to increase refraction for near objects
Presbyopia
Fills the anterior and posterior chambers between the cornea and lens
Aqueous Humor
A clear, watery liquid secreted by ciliary bodies to provide nourishment to lens and cornea - provides interior pressure to the eye
Aqueous Humor
Where does the aqueous humor drain
Into scleral venous sinus (Canal of Schlemm) and back into the venous blood
What can inadequate drainage of aqueous humor lead to
Glaucoma
Fills the posterior portion of the eye behind the iris and ciliary body
Vitreous Humor
Thick, viscous substance that helps keep the shape of the eyeball
Vitreous Humor
What does the vitreous humor in terms of the retina
Transmit light to the retina
Where are photoreceptors within the retina
In the inner layer (furthest from the front)
Allow black and white vision in low light
Rods
Modified cilium specialized to absorb light within the rods
The outer segment
Contains organelles sitting atop cell body with nucleus within the rods
The inner segment
Visual purple, in high concentration in rods
Rhodopsin
What is happening when light hits the protein within rods and turns yellow and then colorless
Bleaching
Allows dim light vision (more sensitive to light, doesn’t respond to bright light)
Rods
Perception is in gray tone
Rods
Less sensitive to light but allow color vision and greater visual acuity
Cones
Involves three types of cones
Trichromatic vision
Don’t work in dark light
Cones
What explains why we have both rods and cones
Duplicity theory of vision
Specializes in communication and coordination amongst its organs, tissues, and cells
The endocrine system
Organs that are traditional sources of hormones
Endocrine glands
Chemical messengers that are transported by the bloodstream and stimulate physiological responses in cells of another tissue or organ, often a considerable distance away
Hormones
These glands have ducts, carry secretion to an epithelial surface of the mucosa of the digestive tract: “external secretions”
Exocrine glands
These glands have no ducts; contain dense, fenestrated capillary networks which allow easy uptake of hormones into bloodstream. “Internal secretions”
Endocrine glands
Which system reacts quickly, adapts quickly, and targeted and specific (one organ)
The nervous system
Which system reacts slowly and its effects may continue for days or longer, adapts slowly, and has general, widespread effects (many organs)
Endocrine system
Regulates functions from water balance and thermoregulation to sex drive and childbirth - many of its functions are carried out by the pituitary gland
Hypothalamus
The pituitary gland is suspended from the hypothalamus by this stalk
Infundibulum
What is the location and size of the pituitary gland
Housed in the sella turcica of sphenoid bone and is the size and shape of a kidney bean
What is the name of the anterior pituitary
Adenohypophysis
What is the name of the posterior pituitary
Neurohypophysis
The adenohypophysis is linked to the hypothalamus by a network of blood vessels called
The hypophyseal portal system
Which hormones regulate adenohypophysis cells
Hypothalamic hormones
Gonadotropin-releasing hormone releases
Follicle-stimulating hormone
Luteinizing hormone
Thyrotropin-releasing hormone releases
Thyroid-stimulating hormone (thyrotropin)
Corticotropin-releasing hormone releases
Adrenocorticotropic hormone
Prolactin-inhibiting hormone releases
Prolactin
Growth hormone-releasing hormone and somatostatin release
Growth hormone
ACTH
Adrenocorticotropic hormone
CRH
Corticotropin-releasing hormone
FHS
Follicle-stimulating hormone
LH
Luteinizing hormone
GnRH
Gonadotropin-releasing hormone
PIH
Prolactin-inhibiting hormone
TRH
Thyrotropin-releasing hormone
TSH
Thyroid-stimulating hormone
GHRH
Growth hormone-releasing hormone
Which part of the pituitary is nerve tissue and not a true gland
Neurohypophysis
How many hormones are produced in the hypothalamus
Eight - Six regulate the anterior pituitary and two are released into capillaries in the posterior pituitary
What are the other two hypothalamic hormones
Oxytocin (OT) and antidiuretic hormone (ADH)
Where are OT and ADH stored and released
Posterior pituitary
How many principal hormones does the anterior lobe of the pituitary synthesize and secrete
Six - FSH, LH, TSH, ACTH, PRL, GH
Which hormone stimulates secretion of ovarian sex hormones, development of ovarian follicles, and sperm production
Follicle-stimulating hormone (FSH)
Which hormone stimulates ovulation, stimulates corpus luteum to secrete progesterone, stimulates testes to secrete testosterone
Luteinizing hormone (LH)
Which hormone stimulates secretion of thyroid hormone
Thyroid-stimulating hormone (TSH)
Which hormone stimulates adrenal cortex to secrete glucocorticoids
Adrenocorticotropic hormone (ACTH)
Which hormone, after birth, stimulates mammary glands to synthesize milk
Prolactin (PRL)
Which hormone stimulates mitosis and cellular differentiation
Growth hormone (GH)
Which hormone increases water retention, reduced urine volume, and prevents dehydration (part of posterior pituitary)
Antidiuretic hormone (ADH) - also called vasopressin because it can cause vasoconstriction
This hormone is released in a surge during sexual arousal and orgasm
Oxytocin (OT)
This hormone stimulates labor contraction, flow of milk during lactation, and may promote emotional bonding between mother and infant
Oxytocin (OT)
Which hormone secretion can follow a circadian pattern
Pituitary
Neuroendocrine reflexes control..
the posterior pituitary
Increased target organ hormone levels inhibit release of hypothalamic and/or pituitary hormones
Negative feedback
Example of Positive Feedback
Stretching of the uterus increases OT release causing contractions
Growth hormone induces the liver to produce…
Insulin-like growth factors (IGF-1) or somatomedins (IGF-II)
What prolongs the action of GH
IGF-1
The time required for 50% of the hormone to be cleared from the blood
Hormonal half-life
What is the GH half-life
6 to 20 minutes
What is the IGF-1 half-life
About 20 hours
What are the effects of IGF-1 on other targets
- Protein synthesis increases
- Lipid metabolism increases
- Carbohydrate metabolism
- Electrolyte balance
Which hormones secretion is high during the first 2 hours of sleep
Growth hormone
What contributes to aging of tissues and wrinkling of the skin
Lack of protein synthesis
Which gland is attached to the roof of the third ventricle beneath the posterior end of the corpus callosum
The pineal gland
Which gland synthesizes melatonin from serotonin during the night (fluctuates seasonally with changes in day length)
The pineal gland
The largest gland that is purely endocrine (dark reddish-brown color due to rich blood supply)
The thyroid gland
What does the thyroid gland secrete
Thyroxine (T4) and triiodothyronine (T3) in response to TSH
Which hormone stimulates protein synthesis, promotes maturation of the nervous system, increases rates of cellular respiration, and elevates basal metabolic rate
Thyroid hormone
Which gland is found atop the kidneys
The adrenal glands
What does the adrenal gland consists of
The outer adrenal cortex and inner adrenal medulla - function as separate glands
Neural tissues that secretes epinephrine and norepinephrine in response to sympathetic neural stimulation
The adrenal medulla
Glandular epithelium and secretes steroid hormones in response to ACTH - consists of three layers, zona glomerulosa, zona fasciculata, and zona reticularis
The adrenal cortex
What are the functions of the adrenal gland
Secretes hormones made from cholesterol
What are the hormones made from cholesterol called
Corticosteroids or corticoids
What are the three categories of corticosteroids
- Mineralocorticoids
- Glucocorticoids
- Adrenal androgens
What increases secretion of ACTH
Stress
What are the stress hormones
- Glucocorticoids
- Epinephrine
- CRH
Set libido throughout life; large role in prenatal male development
Androgens
Small quantity from adrenals, but this become important after menopause for sustaining adult bone mass
Estradiol
Elongated gland below and behind stomach
The pancreas
Clusters of endocrine cells that secrete hormones that regulate glycemia (blood sugar)
Islets
- Secreted by A or alpha cells
- Released between meals when blood glucose concentration is falling
- In liver, stimulates gluconeogenesis, glycogenolysis, and the release of glucose into circulation raising blood glucose level
- In adipose tissue, stimulates fat catabolism and release of free fatty acids
- Also released to rising amino levels in blood, promotes amino acid absorption, and provides cells with raw material for gluconeogenesis
Glucagon - released from the pancreas
- Secreted by B or beta cells
- Secreted during and after meal when glucose and amino acid blood levels are rising
- Stimulates cells to absorb these nutrients and store of metabolize them, lowering blood glucose levels
- Insufficiency or inaction is cause of diabetes mellitus
Insulin - released from the pancreas
Convert a cholesterol-like steroid into cholecalciferol (Vitamin D3) using UV from the sun
Keratinocytes
- Involved in the production of at least five hormones
- Converts cholecalciferol in calcidiol
- Secretes angiotensinogen (precursor of angiotensin II - a regulator of blood pressure)
- Secretes 15% of erythropoietin (stimulate bone marrow)
- Source of IGF-1 that controls action of growth hormone
The liver
- Play role in production of three hormones
- Convert calcidiol to calcitriol, the active form of Vitamin D (increases calcium absorption by intestine and many other things)
- Secrete renin that converts angiotensinogen to angiotensin I
- Produces 85% of erythropoietin (stimulates bone marrow to produce RBCs)
The kidneys
Secretes two natriuretic peptides in response to an increase in blood pressure
The heart
- Secrete at least 10 enteric hormones secreted by enteroendocrine cells
- Coordinate digestive motility and glandular secretion
Stomach and small intestine
Which hormone released from adipose tissue slows appetite (a low count results in weight gain)
Leptin
How are hormones taken up and degraded when they have served their purpose
By the liver and kidney - excreted in bile or urine
- Rate of hormone removal from the blood
- Half life: time required to clear 50% of hormone from the blood
- The faster this is, the shorter the half-life
Metabolic clearance rate (MCR)
Not an organ system, but a cell population that inhabits all organs and defends the body from agents of disease
The immune system
Disease-causing agents
Pathogens
Inherited immunity
Innate (nonspecific) immunity
Learned from exposure to specific pathogens, function of lymphocytes
Adaptive (specific) immunity
- Makes it mechanically difficult for microorganisms to enter the body
- Toughness of keratin
- Mostly dry and nutrient-poot for microbial growth
The skin
Thin film of lactic and fatty acids from sweat and sebum that inhibits bacterial growth
Acid mantle
- Found in the digestive, urinary, and respiratory tracts and of the eye
- Impedes entry and attachment of bacteria
Mucous membranes
Engulfs/kills pathogens
Phagocytes
Are the first to arrive at an infection - form pus
Neutrophils
Immobile in the walls of organs and remove pathogens from lymph
Fixed phagocytes
Neutrophils and monocytes squeeze through gaps in post-capillary venule walls to enter tissue in a process called
Extravasation, or diapedesis
The following of a chemicals and attracted to the site - done so by cytokines called chemokines
Chemotaxis
May be released before fusion is complete, killing the cell, and contributing to local inflammation
Lysosomal enzymes
Perform housecleaning functions such as removing cell remnants from cell apoptosis
Macrophages
An abnormal elevation of body temperature (innate immunity)
Fever
An adaptive defense mechanism that, in moderation, can do more good than harm - regulated by the preoptic area of the hypothalamus that acts as a thermostat
Fever
Chemicals that provoke PGE2 release
Pyrogens
Usually triggered by exogenous pyrogens
Fever
Inhibit Prostaglandin E2 synthesis (fever-reducing medications)
Antipyretics
- Inhibits multiplication of temperature-sensitive microorganisms
- Impedes nutrition of bacteria by reducing the availability of iron
- Increases metabolism and stimulates immune reactions
- Promotes interferon activity
- Elevates metabolic rate and accelerates tissue repair
Fever
Redness caused by increased circulation and vasodilation in the injured tissue
Rubor
Warmth caused by the heat given off by the increased flow of blood
Calor
Swelling caused by fluid escaping into the tissues
Tumor
Pain caused by the stimulation of nerve endings
Dolor
- Degranulate and secrete heparin, histamine, serotonin, protease enzymes, vasoactive molecules, pro-inflammatory cytokines, prostaglandins, and other molecules
- Produce warmth, swelling, and pain
- Recruit more leukocytes
Mast cells
- Kill microorganisms through phagocytosis
- Release NETS to trap pathogens
- Undergo programmed cell death and spill protein-digesting enzymes into the surrounding tissues, causing pus
- Release granule proteins that draw monocytes to the area
Neutrophils
- Enlarge into macrophages
- Phagocytose apoptotic neutrophiles and release growth factors and other agents that will end inflammation and promote repair
Monocytes
Produce antibodies against bacterial antigens
B lymphocytes
What causes the sensation of pain
Release of PGE2
The acquired ability to defend against specific pathogens after exposure to these pathogens (mediated by antigens and antibodies)
Adaptive immunity
Cell surface molecules that stimulate the production of specific antibodies and combine with those antibodies
Antigens
- Humoral immunity
- Mature in the bone marrow
B Lymphocytes (B cells)
Type of B cell - produces antibodies
Plasma B cells
Type of B cell - stick around for years in case same antigen is presented again
Memory B cells
What are the types of antibodies
- IgG
- IgA
- IgE
- IgM
- IgD
A group of plasma proteins activated by the binding of antibodies to antigens
Complement
Serves as a recognition protein - part of complement system
C1
Serve as activators - part of complement system
C2, C3, and C4
Attack by attaching to a cell membrane and destroying it - called complement fixation
C5 to C9
- Mature in the thymus gland
- Destroy body cells that harbor foreign antigens
Killer (cytotoxic) T Lymphocytes
Attack the cells directly - destruction means T cells must touch the target victim
Cell-mediated immunity
- Surface molecule is CD4
- Improve ability of B lymphocytes to become plasma cells that secrete specific antibodies and enhance ability of cytotoxic T cells to kill targets
Helper T Lymphocytes
Inhibit response of B lymphocytes and killer T lymphocytes - once pathogen is gone, the immune response can be stopped
Regulatory T Lymphocytes
After infection, it takes 5 to 10 days before antibodies are detected in the blood and the person will get sick
Active immunity - primary response
Later exposure to the same infection results in maximum antibody production in less than 2 hours and the person will likely never get sick
Active immunity - secondary response
Exposure to a live pathogen
Natural Active immunity
Exposure to an attenuated/deactivated pathogen
Artificial Active immunity
Receiving antibodies or immunoglobulin from an outside source
Passive Immunity
From mother to fetus or from mother to child via breast milk
Natural Passive immunity
Receiving of intravenous immunoglobulin, monoclonal antibodies
Artificial Passive immunity
