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RIOS SALADO BIO202 EXAM 1: REAL EXAM
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The heart is a very important muscle in our body that keeps blood flowing to our tissues to keep them nourished with oxygen and help transport carbon dioxide waste to the lungs for gas exchange. The heart uses electrical impulses from specialized nodes to trigger the cardiac muscles to contract, which in turn leads to the continuous pumping function of the heart. The specialized nodes of the heart are the sinoatrial (SA) node and the atrioventricular (AV) node. The SA node is located in the right atrium and is inferior to the superior vena cava entrance. The SA node is the pacemaker of the heart and sets the rate of depolarization that begins the electrical signal that tells the heart to contract. The AV node is located in the lower atrial septum at the junction of the atria and ventricles. The AV node's function is to delay the contraction of the ventricles until the atrial contraction is complete for 0.1s. The - Correct Answer On Exam 1 you will be presented with an essay question. The essay topic is cardiac impulse generation. You will be asked to compose an essay about the cardiac impulse generation and conduction. a. A discussion cardiac conduction should begin with description of the specialized nodes (autorhythmic character) of the heart and their locations. b. The sequence should be discussed as well as coordinating location in the heart.
c. The actual innervation of the cardiac muscle and appropriate structures should be considered. d. Correlation between the stages of impulse should be related to the flow of blood, contraction of the chambers and open and closing of the valves. second great control system of the body that interacts with the nervous system to coordinate and integrate the activity of body cells - Correct Answer Endocrine system o Influences metabolic activity by means of hormones (chemical messengers secreted by cells into the extracellular fluid)
- Reproduction
- Growth and development
- Maintenance of electrolyte, water, and nutrient balance of the blood
- Regulation of cellular metabolism and energy balance
- Mobilization of body defenses - Correct Answer What does the Endocrine system influence? the scientific study of hormones and the endocrine organ - Correct Answer Endocrinology neural functioning plus releases hormones (hypothalamus) - Correct Answer Neuroendocrine organ chemicals that exert their effects on the same cells that secrete them, short- distance signals (smooth muscle cells to contract smooth muscle cells) - Correct Answer Autocrines
based hormones, no thyroid, use g proteins) or lipid-soluble hormones (steroid and thyroid hormones) act on receptors inside the cells which directly activates genes, hormone typically produce one or more of these changes: i. Alters plasma membrane permeability or membrane potential, or both, by opening or closing ion channels ii. Stimulates synthesis of enzymes and other proteins within the cell iii. Activates or deactivates enzymes iv. Induces secretory activity v. Stimulates mitosis - Correct Answer Target cells
- cAMP (second messenger) ii. Hormone binds receptor (hormone acts as first messenger) iii. Receptor activates G protein (G protein activated by GDP: off, GTP: on) iv. G protein activates adenylate cyclase (enzyme) v. Adenylate cyclase converts ATP to cAMP vi. Cyclic AMP activates protein kinases (enzymes that add a phosphate group to proteins, can activate or inhibit certain proteins) - Correct Answer The Cyclic AMP signaling Mechanism
- Intracellular calcium ions (second messenger) ii. Phospholipase C (enzyme) splits a plasma membrane phospholipid, PIP2, into 2 second messengers (DAG: activates protein kinase enzyme and triggers responses within target cell) (IP3: releases Ca2+ from intracellular storage sites, acts as secondary messenger and binds to protein calmodulin which activates enzymes that amplify the cellular response) - Correct Answer PIP2-Calcium Signaling Mechanism Target cells First Mechanism: Cyclic AMP Signaling Mechanism
Second Mechanism: PIP2- Calcium Signaling Mechanism - Correct Answer Describe the two major mechanisms by which hormones bring about their effect on their target tissues a. Negative feedback mechanism: reaction that causes a decrease in function (some internal or external stimulus triggers hormone secretion) b. Humoral stimuli: simplest endocrine control, secrete hormones in direct response to changing blood levels of certain critical ions and nutrients (insulin, Ca2+ levels, aldosterone) c. Neural stimuli: nerve fibers stimulate hormone release (stress: norepinephrine or epinephrine) d. Hormonal stimuli: release hormones in response to hormones produced by other endocrine organs (releasing and inhibiting hormones produced by the hypothalamus regulate the secretion of most anterior pituitary hormones) - Correct Answer Explain how hormone release is regulated a. Blood levels of the hormone b. Relative numbers of receptors for that hormone on or in the target cells c. Affinity (strength) of the binding between the hormone and the receptor - Correct Answer Identify factors that influence activation of a target cell persistently low levels of a hormone can cause its targets to form additional receptors for that hormone - Correct Answer Up-regulation prolonged exposure to high hormone concentrations can decrease the number of receptors for that hormone - Correct Answer Down-regulation
Describe structural and functional relationships between the hypothalamus and pituitary gland composed of neural tissue (pituicytes) and nerve fibers, releases neurohormones received by the hypothalamus, hormone-storage area, not true endocrine gland - Correct Answer Posterior pituitary lobe composed of glandular tissue, manufacturers and releases hormones - Correct Answer Anterior pituitary lobe Oxytocin ADH - Correct Answer What two hormones does the posterior pituitary release? stimulates uterine contractions; initiates labor, initiates milk ejection - Correct Answer Oxytocin prevents wide swings in water balance, helping the body avoid dehydration and water overload, substance that inhibits urine formation, stimulates kidney tubule cells to reabsorb water - Correct Answer ADH i. Effects of hyposecretion (less): diabetes insipidus ii. Effects of hypersecretion (more): syndrome inappropriate of ADH secretion (SIADH) - Correct Answer Effects of abnormal secretion of ADH Growth hormone (GH) Thyroid-stimulating hormone (TSH) Adrenocorticotropic hormone (ACTH) Follicle-stimulating hormone (FSH) Luteinizing hormone (LH)
Prolactin (PL) - Correct Answer What hormones does the anterior pituitary release? liver, muscle, bone, cartilage, and other tissues: anabolic hormone; stimulates somatic growth; mobilizes fats; spares glucose, growth promoting effects mediated by IGFs - Correct Answer Growth hormone(GH) i. Effects of Hyposecretion: pituitary dwarfism in children ii. Effects of Hypersecretion: gigantism in children; acromegaly in adults - Correct Answer Effects of abnormal secretion of GH thyroid gland: stimulates thyroid gland to release thyroid hormones - Correct Answer Thyroid-stimulating hormone (TSH) i. Hypersecretion: Cretinism in children, myxedema in adults ii. Hyposecretion: hyperthyroidism; effects similar to those of Graves' disease, in which antibodies mimic TSH - Correct Answer Effects of abnormal secretion of TSH Adrenal cortex; promotes release of glucocorticoids and androgens - Correct Answer Adrenocorticotropic hormone (ACTH) i. Hyposecretion: rare ii. Hypersecretion: Cushing's disease - Correct Answer Effects of abnormal secretion of ACTH ovaries and testes; in females, stimulates ovarian follicle maturation and production of estrogens, in males, stimulates sperm production - Correct Answer Follicle-stimulating hormone (FSH)
regulate the function of the gonads (ovaries and testes) - Correct Answer Gonadotropins located in the anterior neck, on the trachea just inferior to the larynx, largest pure endocrine gland in the body - Correct Answer Thyroid gland Thyroid hormone (TH) Calcitonin - Correct Answer What are the hormones released by the thyroid gland? increasing basal metabolic rate and body heat production by turning on transcription of genes concerned with glucose oxidation (calorigenic effect: heat producing), regulating tissue growth an development (critical for normal skeletal and nervous system development and maturation and for reproductive capabilities), maintaining blood pressure by increasing the number of adrenergic receptors in blood vessels - Correct Answer Thyroid hormone calcitonin is a polypeptide hormone released by the parafolicular or C cells of the thyroid gland in response to a rise in Ca2+ blood levels, targets the skeleton where it inhibits bone resorption and release of Ca2+ from the bony matrix and stimulates Ca2+ uptake and incorporation into bone matrix - Correct Answer Calcitonin a. Thyroglobulin is synthesized and discharged into the follicle lumen b. Iodide is trapped (once trapped inside the follicular cell, iodide moves into the follicle lumen by facilitated diffusion) c. Iodide is oxidized to iodine
d. Iodine is attached to tyrosine (attachment of one iodine to tyrosine produces MIT, monoiodotyrosine and attachment of two iodines produces diiodotyrosine, DIT) e. Iodinated tyrosines are linked together to form T3 and T4 (two linked DITs = T4, MIT + DIT = T3) f. Thyroglobulin colloid is endocytosed (to secrete hormones, the follicular cells must reclaim iodinated thyroglobulin by endocytosis and combine the vesicles with lysosomes) g. Lysosomal enzymes cleave T4 and T3 from thyroglobulin and the hormones diffuse from the follicular cell into the bloodstream - Correct Answer Follow the process of thyroxine formation and release pyramid-shaped organs perched atop the kidneys, where they are enclosed in a fibrous capsule and a cushion of fat - Correct Answer Adrenal glands knot of nervous tissue, part of sympathetic nervous system, one of two adrenal glands - Correct Answer Adrenal medulla outer adrenal gland, encapsulates the medulla and forms the bulk of the gland, glandular tissue derived from embryonic mesoderm - Correct Answer Adrenal cortex adrenal cortex synthesizes over two dozen steroid hormones - Correct Answer Corticosteroids regulate the electrolyte concentrations in extracellular fluids (Na+ and K+), hormones that help control the balance of minerals and water in blood (outer layer: Zona glomerulosa) i. Example: Aldosterone
an amine hormone derived from serotonin - Correct Answer Melatonin Important to our biological clock, bright light suppresses melatonin whereas darkness allows us to produce melatonin to become sleepy, changing melatonin levels may influence rhythmic variation is physiological processes such as body temperature, sleep, and appetite - Correct Answer What is the importance of melatonin? soft tadpole-shaped gland composed of endocrine and exocrine glands located behind the stomach - Correct Answer Pancreas tiny cell clusters that produce pancreatic hormones o Alpha cells: glucagon synthesizing cells o Beta cells: insulin synthesizing cells - Correct Answer Pancreatic islets Glucagon Insulin - Correct Answer What hormones does the pancreas secrete? 29 amino acid polypeptide, potent hyperglycemic agent, target: liver i. Breakdown of glycogen into glucose, synthesis of glucose from lactic acid and from non-carbohydrate molecules, release of glucose to the blood by liver cells, causing blood glucose levels to rise ii. Lower blood levels of amino acids as the liver cells sequester these molecules to make new glucose molecules iii. Alpha cells prompt glucagon secretion - Correct Answer Glucagon small 51 amino acid protein consisting of two amino acid chains linked by disulfide bonds, lowers blood glucose levels, promotes protein synthesis and fat
storage, participates in neuronal development, feeding behavior, and learning and memory i. Circulating insulin lowers blood glucose levels by:
- Enhances membrane transport of glucose into most body cells, especially muscle and fat cells
- Inhibits the breakdown of glycogen to glucose
- Inhibits the conversion of amino acids or fats to glucose, counter any metabolic activity that would increase plasma levels of glucose - Correct Answer Insulin responsible for maturation of the reproductive organs and the appearance of the secondary sex characteristics of females at puberty, breast development, and the menstrual cycle - Correct Answer Estrogens and Progesterone (Ovaries) initiates the maturations of the males reproductive organs and the appearance of secondary sex characteristics and sex drive, normal sperm production, maintains the reproductive organs in their mature functional state in adult males - Correct Answer Testosterone (Testes) sustains the fetus during pregnancy, secretes steroid and protein hormones that influence the course of pregnancy - Correct Answer Estrogens, Progesterone, human chorionin gonadotropin (hCG) Placenta stomach, intestine, pancreas - Correct Answer Where are enteroendocrine cells located? i. Leptin: tells your body how much stored energy (as fat) you have
- Brain, suppresses appetite, increases energy expenditure ii. Resistin: insulin antagonist (fat, muscle, liver)
tolerance declines, thyroid hormone synthesis decreases - Correct Answer Explain the effects of aging and stress on the endocrine system located in the throat, bilobed gland connected by an isthmus - Correct Answer Thyroid gland location regulate blood calcium levels, decreases
- Produced by parifollicular cells of the thyroid - Correct Answer What does Calcitonin do? broken into T4/T3: control the rate of body metabolism and cellular oxidation
- Release stimulated by another hormone
- Produced by follicular epithelial cells of the thyroid
- T4 (thyroxine)
- Hyposecretion: low BMR, mental and physical sluggishness
- Hypersecretion: nervousness, irregular pulse rate, sweating - Correct Answer What does TH do and what is it broken down into? found close to the kidney - Correct Answer Adrenal gland location Corticoids - Correct Answer What does the adrenal cortex produce? Mineralocorticoids Glucocorticoids Gonadocorticoids - Correct Answer What are corticoids broken down into? regulate water and electrolyte balance in the extracellular fluids o Aldosterone: maintenance of salt water balance in the extracellular fluid
- Release stimulated by humoral factors (the concentrations of specific nonhormonal substances in the blood or extracellular fluid) o Produced by zona glomerulosa cells - Correct Answer What do mineralocorticoids do? enable the body to resist long-term stressors, by increasing blood glucose levels o Cortisone: released in response to stressors o Hydrocortisone o Corticosterone o Produced by zona fasciculata cells in the adrenal gland - Correct Answer What doe glucocorticoids do? chiefly androgens, but some estrogens are formed
- Estrogen
- Testosterone - Correct Answer What do gonadocorticoids do? Epinephrine Norepinephrine - Correct Answer What does the Adrenal Medulla produce? released in response to stressors, mimics the sympathetic nervous system, response to relax 80% - Correct Answer Epinephrine response to stress 20%
- Release stimulated by the nervous system - Correct Answer Norepinephrine a mixed gland, located close to the stomach and small intestine - Correct Answer Pancreas location Glucagon
- Hypersecretion: demineralization of bones, spontaneous fractures
- Produced by chief cells - Correct Answer What does PTH do? found in the pelvic cavity of the female, concerned with ova and female hormone production - Correct Answer Ovaries location Estrogen Progesterone - Correct Answer What do the ovaries produce? drive development of secondary sexual characteristics, directly responsible for the regulation of the menstrual cycle
- Released due to the stimulation of another hormone
- Hyposecretion: sexual immaturity - Correct Answer What does Estrogen do? directly responsible for the regulation of the menstrual cycle - Correct Answer What does progesterone do? found in the upper thorax overlying the heart, large during youth - Correct Answer Thymus location Thymosin Thymopoietin - Correct Answer What does the thymus produce? programming of T lymphocytes - Correct Answer What does thymosin do? found in the roof of the third ventricle - Correct Answer Pineal gland location Melatonin - Correct Answer What does the pineal gland produce?
helps regulate the sleep-wake cycle, and prevent precocious sexual maturation - Correct Answer What does melatonin do?
- Correct Answer Anterior Pituitary location ACTH FSH LH TSH PRL MSH GH - Correct Answer What does the anterior pituitary produce? regulate the function of another endocrine gland (tropic hormone)
- Produced by basophil cells of the anterior pituitary - Correct Answer What does ACTH do? regulate the function of another endocrine gland (tropic hormone), regulate the ovarian cycle
- Release stimulated by another hormone
- Produced by basophil cells of the anterior pituitary - Correct Answer What does FSH do? regulate the function of another endocrine gland (tropic hormone), regulate the ovarian cycle
- Produced by basophil cells of the anterior pituitary - Correct Answer What does LH do? regulate the function of another endocrine gland (tropic hormone)
