Chapter 7 & 8: Homeostasis Flashcards
Ureters
Tubes that conduct urine from the kidneys to the bladder.
Urethra
Tube that carries urine from the bladder to the exterior of the body.
Cortex
The outer layer of the kidney
Medulla
The area inside of the cortex.
Renal Pelvis
the area where the kidney joins the ureter.
Nephrons
Functional Units of the kidneys
Afferent Arterioles
Small branches that carry blood to the glomerulus.
Glomerulus
High- Pressure capillary bed that is the site of filtration.
Efferent Arterioles
Small branches that carry blood away from the glomerulus to a capillary net.
Peritubular Capillaries
A network of small blood vessels that surround the nephron.
Bowman’s Capsule
Cuplike structure that surrounds the glomerulus.
Proximal Tubule
Section of the nephron joining the Bowman’s capsule with the loop of Henle
Loop of Henle
Carries filtrate from the proximal tubule to the distal tubule.
Distal Tubule
Conducts urine from the loop of Henle to the collecting duct.
Collecting Duct
Tube that carries urine from nephrons to the pelvis of a kidney.
Filtration
The process by which blood or body fluids pass through a selectively permeable membrane.
Reabsorption
Transfer of glomerular filtrate from the nephron back into the capillaries.
Secretion
Movements of materials, such as ammonia and some drugs, from the blood back into the distal tubule.
Threshold Level
The maximum amount of material that can be moved across the nephron.
Interstitial Fluid
The fluid that surrounds the body cells
Antidiuretic hormone (ADH)
Causes the kidneys to increase water reabsorption.
Osmoreceptors
Specialized nerve cells in the hypothalamus that detect changes in the osmotic pressure of the blood and surrounding extracellular fluids (ECF).
Homeostasis
The process by which a constant internal environment is maintained despite changes in the external environment.
Dynamic Equilibrium
A condition that remains stable within fluctuating limits.
Negative Feedback
The process by which a mechanism is activated to restore conditions to their original state.
Positive Feedback
Process by which a small effect is amplified.
Thermoregulation
Maintenance of body temperature within a range that enables cells to function efficiently.
Hypothalamus
Region of the vertebrate’s brain responsible for coordinating many nerve and hormone functions.
Deamination
Removal of an amino group from an organic compound.
Urea
Nitrogen waste formed from two molecules of ammonia and one molecule of carbon dioxide.
Uric Acid
Waste product formed from the breakdown of nucleic acids.
Contractile Vacuole
A structure in unicellular organisms that maintains osmotic equilibrium by pumping fluid out from the cell.
Aldosterone
Hormone that increases Na+ reabsorption from the distal tubule and collecting duct.
Xenotransplants
Transplants from one species to another; the word xeno means “strange” or “foreign”.
Transgenic Animals
Animals that have genes from other species incorporated into their DNA.
Hormones
Chemicals released by cells that affect cells in other parts of the body.
Endocrine Hormones
Chemicals secreted by endocrine glands diectly into the blood.
Growth Hormone (GH)
Hormone, produced by the pituitary gland, that stimulates growth of the body; also known as somatotropin (STH).
Insulin
Hormone produced by the islets of Langerhans in the pancreas; insulin in secreated when blood sugar levels are high.
Epinephrine
Hormone, produced in the adrenal medulla, that accelerates heart rate and body reactions during a crisis (the fight-or-flight response); also known as adrenaline.
Steroid Hormones
Group of hormones, made from cholesterol, that includes male ans female sex hormones and cortisol.
Cortisol
Hormone that stimulates the conversion of amino acids to glucose by the liver.
Protein Hormones
Group of hormones, composed of chains of amino acids, that includes insulin and growth hormone.
Unused protein Hormones
Protein hormones that do not attach to receptor molecules on target cells are removed from the bod by the liver or kidney. The presence of these hormones can be monitored by urinalysis.
Homeostasis is best defined as…
a feedback system designed to maintain body systems within an optimal range while responding to environmental or external change
A rapid increase in external temperature would be followed by which homeostatic adjustment in humans?
an increase in blood flow to the arms and an increase in perspiration
Nitrogen wastes from the breakdown of proteins and amino acids are removed from the body by the…
conversion of ammonia to urea in the liver and filtration by the kidney
An increase in blood pressure in the glomerulus would cause…
an increase in filtration and an increase in urine output
Concentrated urine is produced when ADH is…
abundant and the collecting duct is permeable to water
After a severe cut to the skin, the production of urine temporarily decreases. This can be explained by the drop in blood pressure, which causes…
the release of aldosterone, which increases Na+ reabsorption in the nephron, leading to increased water reabsorption.
Which of the following describes a negative feedback reaction?
LH stimulates the interstitial cell to produce testosterone, which inhibits the release of LH.
Glucagon is produced in an organ and affects target cells that are in another part of the body. The organ of production and the location of the target cells are, respectively, which of the following?
pancreas and liver
Two hormones that adjust body systems for short-term stress and long-term stress, respectively, are which of the following?
epinephrine and cortisol
In times of stress, under the influence of cortisol, levels of amino acids increase in the blood. Why is this change beneficial as a response to stress?
The amino acids are converted to glucose by the liver, raising blood sugar, thereby providing more energy to deal with stress.
Which of the following would be the result of hypersecretion of the thyroid gland?
a tendency not to gain weight, a warm peripheral body temperature, and a high energy level
Identify a glucocorticoid released by the adrenal cortex.
cortisol
Which one of the following choices signifies the beginning of menstruation?
FSH and LH secretions decrease and the corpus luteum deteriorates.
A laboratory animal is accidentally given too much insulin and begins convulsing. What could you do to quickly return the animal to a normal blood sugar?
provide sugar in a fruit drink
Cyclic Adenosine Monopoasphate (cyclic AMP)
Secondary chemical messenger that directs the synthesis of protein by ribosomes
Thyroxine
iodine-containing hormone, produced by the thyroid gland, that increases the rate of body metabolism and regulates growth.
Pituitary Gland
gland at the base of the brian that, together with the hypothalamus, functions as a control centre, coordinating the endocrine and nervous systems.
Glucagon
A hormone produced by the pancreas; when blood sugar levels are low; glucagon promotes conversion of glycogen to glucose.
Diabetes
Chronic diseases that occurs when the body cannot produce any insulin or enough insulin, or is unable to use properly the insulin it does make.
Adrenal Medulla
found at the core of the adrenal gland, the adrenal medulla produces epinephrine and norepinephrine.
Adrenal Cortex
outer region of the adrenal gland that produces glucocorticoids and mineralocorticoids
glucocorticoids
various hormones, produced by the adrenal cortex, designed to help the body meet the demands of stress.
Removing the adrenal medulla
The adrenal medulla can be surgically removed without any apparent ill effects. If the adrenal cortex removed, however, death would result.
mineralocorticoids
hormones of the adrenal cortex important for regulation of salt-water balance.
Prostaglandins
hormones that have pronounced effect in a small localized area.
Anabolic Steroids
substances that are designed to mimic many of the muscle-building traits of the sex hormone testosterone.
Testosterone
male sex hormone produced by the intersitial cells of the testes.
Spermatogenesis
process by which spermtogonia divide and differentiate into mature sperm cells
Gonadotropic Hormones
Hormones produced by the pituitary gland that regulate the functions of the testes in males and the overies in females.
Follicle-stimulating Hormone (FSH) - in males
in males, hormone that increases sperm production
Iuteinizing Hormone (LH)
in males, hormone that regulates the production of testosterone
Gonadotropin-releasing Hormone (GnRH)
Chemical messenger from the hypothalamus that stimulates secretions of FSH and LH from the pituitary.
Follicles
structures in the ovary that contain the egg and secrete estrogen.
Ovulation
release of the egg from the follicle held within the ovary
Corpus Luteum
a mass of follicle cells that forms within the ovary after ovulation; secretes estrogen and progesterone
Flow phase
phase of the menstrual cycle marked by shedding of the endometrium
Follicular phase
phase marked by development of ovarian follicles before ovulation
Estrogen
female sex hormone that activates the development of female secondary sex characteristics, including development of the breasts and body hair, and increased thickening of the endometrium.
Luteal phase
phase of the menstural cycle characterized by the formation of the corpus luteum following ovulation
Progesterone
female sex hormone produced by the ovaries that maintains uterine lining during pregnancy.
Follicle-stimulating hormone (FSH) - in females
in females, a gonadotropin that promotes the development of the follicles in the ovary.
luteinizing hormone (LH)
in females, a gonadotropin that promates ovulation and the formation of the corpus luteum.
