T/F: In salivary glands both branches act together to produce maximal secretion.
True. In most tissues innervated by the autonomic nervous system, the sympathetic & parasympathetic braches have opposing effects.
Amylase contained in saliva begins the digestion of which type of nutrients?
Proteolytic enzyme precursor.
Stimulates stomach mobility and secretions.
stomach contents, contents of small intestine
Major stimulators of stomach motility: Major inhibitors of stomach motility:
The intrinsic nervous system
The chief regulator of gastrointestinal functions.
Fats, proteins, starches, nucleic acids
What is digested by pancreatic seretions
Derived from cholesterol and emulsify fats in the small intestine.
mucus is secreted NaCl and water are absorbed Fecal matter is stored 18-24 hours Amino acids, fatty acids, and sugars are aborbed.
H+ and Cl- (HCl, hydrochloric acid)
Secreted by parietal (oxyntic) cells of the stomach, this activates proteolytic enzymes.
The smooth muscle bands of the large intestine.
Determines the intensity/loudness of sound?
# of sensory units stimulated and the frequency of their action potentials.
Sensations of angular motion are mediated by the semicircular canals and a person normally has six of them.
Sensations of sound & linear & angular motion are all initiated by receptor potentials that arise w. the stereocilia of hair cells are displaced.
Epi. & thyroid hormones are all derived from the amino acid, tyrosine, & act by binding to receptors on target cell's surface & generate 2nd messengers w/in the cell.
How is a protein hormone best described?
Stored within the cells where it is synthesized, dissolves in plasma and acts on target cells by binding to a receptor on the cells' serface
Characteristic shared by steroid hormones, thyroid hormones, and 1,25(DH)D3 (calcitrol)?
All enter target cells and bind to a receptor inside the cell. Circulate bound to a carrier protein All change the rate of transciption of specific messenger RNAs.
The half-life of a hormone is 30 min & it's plasma concentration is 300mg/ml. If hormone secretion stops, what is the concentration after 1 hr?
Hormones from the posterior pituitary gland are important regulators of anterior pituitary gland secretions.
Effects of growth hormone?
Stimulates bone growth by increasing insulin-like growth factor.
Antiduretic hormone increases reabsoption of water in nephrons & is vasopressin b/c @ higher concentrations, it has vasocontrictor effects that + BP.
Which hormone is most active in promoting the uptake, use, and storage of energy-yielding substrates?
Describe the fasting state.
Plasma concentration of glucagon>insulin. Plasma glucose is derived from glycogenolysis and gluconeogenesis. Lipolysis in adipose tissue is stimulated.
Shared characteristic of diabetes mellitus and diabetes insipidus?
Both are characterized by polyuria and polydipsia.
T/F: Secretion of both epinephrine and cotisol by adrenal glands is stimulated by adrenocorticoptropic hormone from the enterior pituitary gland.
T/F: Aldosterone and cortisol are both secreted by the adrenal cortex, the secretion of each is controlled by different factors.
Primary calcium sensor of the body?
What does parathyroid hormone do?
Stimulates synthesis of 1,25(DH)D3 (calcitrol), stimulates reabsorption of CA2+ by nephrons of the kidneys, increases reabsorption of bone.
What does 1,25(DH)D3 (calcitrol) do?
Increases the absorption of dietary CA2+
Where is blood pumped when it leaves the pulmonary circulation?
The left atrium.
How to best describe transpulmonary pressure (Ptp)?
Normally always positive. Equal to the alveolar pressure (Palv) minus the intrapleural (Pip) pressure. When transpulmonary pressure exceeds atomospheric pressure air leaves the lungs.
Thoracic pressure and volume change in opposite directions.
Principal difference between central and peripheral chemoreceptors?
Peripheral chemoreceptors respond to changes in PO2 and pH, central chemoreceptors respond only to changes in pH.
What are essential factors in blood clotting?
Ca2+ Fibrin Platelets
T/F: Agglutination (clumping) of red cells is an immunologic response mediated by antigens & antibodies & is unrelated to blood clotting.
How is skeletal muscle stimulated?
By alpha motor neurons of the somatic nervous system.
What do the uterus, gastrointestinal tract wall, and urinary and gall bladders have in common?
All composed mostly of smooth muscle.
What structure attaches a muscle to bone and transmits force generated during contraction?
How is the thin filament of a skeletal muscle best described?
Made up of actin, troponin, and tropomyosin.
Which of the following shortens during skeletal muscle contraction?
Which compound binds CA2+ when skeletal muscle is stimulated?
Which of the following best describes skeletal muscle contraction?
Results from the cyclical binding and unbinding of actin-myosin cross bridges.
A transverse tubule
An extension of the plasma membrane that opens a Ca2+ release channel.
Contains a membrane-bound ATPase that forms a Ca2+ store within skeletal muscle cells.
Undergoes a shape change that exposes a myocin binding site on actin.
Most important factor determining how much force a skeletal muscle can generate?
The # of actin-mysoin cross bridges formed.
Is actin an ATPase?
T/F: #1 factor in determining length-tension relationship in skeletal & smooth muscle is the degree of overlap of thick & thin filaments.
With what compound in smooth muscle does Ca2_ interact directly?
In smooth msucle, what activates myosin enabling it to form a cross bridge with actin?
Phosphorylation of myosin's light chain.
Functional important of being more actin in smooth muscle than in skeletal muscle and that actin fibers are longer in smooth than in skeletal muscle?
Smooth muscle can generate force over a wider range of stretch than can skeletal muscle..
In skeletal muscle, how do recruitment (quantal summation) and temporal summation (tetanus) differ?
Quantal summation can't generate as much force as temporal summation, and requires less time to generate maximum force. During temporal summation the Ca2+ concentration inside muscle cells is much higher than during quantal summation.
How are cells of a single unit smooth muscle able to act as a unit?
They are electrically coupled by gap junctions so depolarization spreads directly from cell to cell.
Which of the following components of a skeletal muscle twitch are ordered correctly from shortest to longest duration?
How is generated force generation obtained in a skeletal muscle when each motor unit is responding in an all or none fashion?
Different motor units have different thresholds so increasing stimuli activate more motor units.
Why is the force developed by a skeletal muscle during tetanus > the force developed by same muscle during a twitch stim. by 1 supramaximal stim?
Because frequent stimuli increase Ca2+ concentration in muscle cels more than does a single stimulus so more cross bridges form.
What accounts for the latent period in skeletal muscle?
CA2+ is released from the sarcoplasmic reticulum. Ca2+ binds to a protein assoiated with the thin filaments. Proteins udergo shape changes to uncover myosin binding sites.
What part of a spinal cord is NOT involved in a spinal reflex?
Which spinal reflex has only 1 synapse in the spinal cord?
The tendon stretch (knee jerk) reflex.
How do suprasegmental reflexes differ from segmental or intersegmental reflexes?
Suprasegmental reflexes require the brain, other reflexes don't.
During certain spinal reflexes an extensor muscle group is stimulated. What happens to the flexor muscle group that opposes the stimulated extensor?
It will be relaxed because its alpha motor neurons will be hyperpolarized by spinal cord interneurons.
Why is the tendon stretch (knee jerk) reflex faster than other spinal reflexes?
Because it is the spinal reflex with the fewest synapses.
How are the cutaneous senses best described?
They are widely distributed and associated with the skin.
What is the adequate stimulus of a sensory receptor?
It is the form of energy to which the receptor is most sensitive.
T/F: Sensory receptors typically convert electrical energy into different forms of energy (chemical, light, pain).
How does the sense of pain differ from other sensory systems?
Sensations of pain can be mediated by any neuron responding to the products of tissue damage.
How is the intensity of a stimulus coded in sensory systems?
More intense stimuli evoke more frequent action potentials from a greater number of sensory units than do lesser stimuli.
What type of receptor continues to repsond as long as the stimulus is present?
A tonic receptor.
What do the senses of taste and smell have in common?
Both respond to chemicals in solution.
T/F: Different wavelengths of visible light are perceived as different colors.
How is the fovea centralis of the eye best described?
It is the part of the retina where cones are located and detail in vision is greatest.
How is the system of ciliary muscle and zonular fibers in the eye best described?
It regulates lens thickness to allow focusing of objects at different distances.
How is the image of an object focused on the retina?
Convex surfaces of both cornea and lens refract light to a focal point on the retina.
Where does the optic nerve carry information?
The optic nerve carries info to the visual cortex via the thalamus, the the hypothalamus to regulate daily/seasonal changes, and the the superior colliculus to regulate occular reflexes.
Which of the following peripheral nervous sytems can either stimulate or inhibit the organs they innervate.
The autonomic nervous system.
What would be the effect of a drug that prevented the release of acetylcholine form all nerve terminals?
Skeletal muscles would be paralyzed. Parasympathetic nervous system would stop working. Sympathetic nerovus system would stop working.
It is a modified sympathetic ganglion that secretes epinephrine into the bloodstream when it is stimulated during the flight or fight response.
When a neuron in the autonomic nervous system releases a neurotransmitter, what is the most important determinant of the response?
The receptor on the effector organ.
Describe the course of blood flow in the heart and pulmonary circulation.
Right atrium to right ventricle to pulmonary circulation to left atrium to left ventricle to aorta.
Describe the valves of the heart.
They open and close in response to pressure differences and allow flow in only one direction.
What part of the heart initiates the cardiac cycle under normal conditions?
The sinoatrial (SA) node.
What is the function of the intercalclated sic that joins heart muscle cells?
It forms a mechanical link that transmits force efficiently.
Which cells in blood vessels are in direct contact with the blood?
Endothelial cells of the tunica intima.
What characterizes all arteries?
They carry blood away from the heart.
Contain most of the blood volume.
They conduct blood and maintain blood pressure during diastole.
They are the primary resistance vessels.
Which blood vessels are made up of a single layer of cells and are specialized to maximize exchange?
How is blood distribution regulated so that the GI tract gets a lot of blood after a meal and skeletal muscle gets a lot of blood during exercise?
The ANS regulates constriction and relaxation of arteriorlar smooth muscle to decrease or increase blood supply according to metabolic needs.
T/F: When vagus nerve activity increases heart rate falls.
What accounts for most of the time occupied by the P-R interval?
Conduction across the atrioventricular (AV) node.
What causes the T wave?
Repolarization of the ventricles.
What causes the P wave?
Depolarization of the atria
Which properties does cardiac muscle share with skeletal muscle?
It is striated and constriction is regulated by Ca2+ binding to elements of the thin filaments.
Which properties does cardiac muscle share with smooth muscle?
Ca2+ enters the cell from outside and triggers the release of more Ca2+ from stores within the cell.
The length-tension relationship of cardiac muscle is the physiologic basis of what law of the heart?
Starling's law of the heart. An increase in end diastolic volume is followed by an increase in the subsequent stroke volume.
What percent of body weight is due to water?
Which body fluids compartments have very similar ionic compositions?
Plasma and interstitial fluid.
What distinguishes the capillaries of the flomerulus from most other capillaries in the body?
Blood pressure within them is higher than most other capillaries. They empty into an arteriole rather than into a venule. Their structure is specialized to maximized filtration along their whole length.
Which materials are not filtered at the glomerulus but remain within the capillaries?
Cells and proteins.
In which part of the nephron is filtration the predominant process?
In which part of the nephron does most reabsorption take place?
The proximal convoluted tubule.
T/F: Because of intrinsic myogenic control, glomerular filtration rate is constant over a wide range of mean arterial blood pressure.
What will happen when compound X exceeds its renal threshold?
Compound X will be excreted in the urine.
A drug inhibits Na+K+ATPase in the renal proximal convoluted tubule. What would most likely result?
Urine volume would rise.
Why does glucose appear in the urine of a person with diabetes mellitus?
Because the glucose concentration in the renal tubules of diabetic persons exceeds the ability of the tubules to reabsorb it.
What is renal plasma clearance?
It is the volume of plasma from which a solute is removed by the kidney.
What compound controls the production of angiotensin II which then increases blood pressure and Na+ conservation?
What compound conserves Na+ by increasing its reabsoption in the distal tubules and collecting ducts?
What function is carried out by the long hairpin shape of the loop of Henle in juxtamedullary nephrons?
It exposes tubular contents to changing osmolarity to increase Na+ and water reabsoption.
Describe antidiuretic hormone (ADH).
Increases the reabsorption of water in the nephrons' collecting ducts. Low level of ADH will produce a large volume of dilute urine. High concentrations of ADH increase blood pressure by constricting blood vessels.
While BP is measured, when is the sound of blood flowing in the artery 1st heard?
When systolic pressure exceeds pressure in the cuff.
Equation for MABP?
Equation for cardiac output?
What would be the effect on the electrocardiogram of a drug that blocks conduction at the atrioventricular (AV) node?
The QRS complex would not follow the P-wave.
Site of spermatogenesis; coiled and convoluted.
Surround seminiferous tubules and produce testosterone.
Network of tubes at base of testes that collect sperm.
Conduct sperm out of testis and into epiddymus.
Duct that concentrates and stores sperm.
Thick walled, made of smooth muscle that moves sperm out.
Paired and secrete into urethra
Single gland, located around the urethra
Secrete into urethra
Copulatory organ (AKA organ of intromission)
Production of sperm. Stim. by FSH from anterior pituitary, under control of GRH. Continuous from puberty.
Highly specialized cells. Only cells in male body that are haploid. Generated via meiosis, take 64 days. Motile via flagellum.
Surround developing sperm. Form blood-testis barrier. Mediate effects of FSH & testosterone on developing sperm.
Granulosa cells make estrogen. Theca cells produce androgens to serve as estrogen precursors. Characterized by low estrogens and progesterone in the beginning, with high estrogen and a spike in lutenizing hormone (LH) at the end.
What happens during the luteal phase
Corpus lutium makes estrogen and A LOT of progesterone. Uterine lining is prepared for implantation. Lowered GNRH due to progesterone and estrogen. If no implantation occurs, lutium regresses, progesterone & estrogen lower.
What kind of feedback loop is the follicular phase?
Follicular phase in ovary. Characterized by growth of endometrium.
Luteal phase in ovary. Increased secretion of endometrial glands in prep for implantation of embryo. Stim. by progesterone & estrogen from corpus lutium.
What are the actions of estrogens?
Stimulates growth of ovary and follicles Stimulates oogenesis Stimulates growth of uterine smooth muscle Stimulates production of thin, watery mucus to aid in sperm transport. Simulates 2ndary sex characteristics. Aids bone growth and affects behavior.
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