BIO Ch. 10 Homeostasis Flashcards
What are the organs of the excretory system?
kidneys, uterus, bladder and urethra
What is the path of urine?
the nephrons empty into the renal pelvis to the uterus down to the bladder and through the urethra to exit out of the body
What is the function of the renal hilium?
point of entry and exit for the renal artery, renal vein, and ureter
What is the difference b/w the afferent and efferent arteriole pathways in the kidneys?
afferent arterioles carry blood towards the glomeruli in the Bowmen’s capsule. efferent arterioles carry blood away from the glomerulus to the vasa recta which is surrounded by nephrons before leaving through the renal vein
What are the waste products secreted in urine?
H+ ions, urea, NH3, K+
How is ammonia excreted?
the liver converts ammonia to urea which travels to the nephrons to be excreted with urine
How is aldosterone secreted?
aldosterone (a steroid) hormone is secreted by the adrenal cortex in response to decreased BP. When secreted, it stimulates the release of renin from the juxtaglomerular cells in the kidney. renin cleaves angiotensinogen, a liver protein that forms angiotensin I. Angiotensin I is metabolized to angiotensin II in the lungs. angiotensin II promotes the release of aldosterone
What is the role of aldosterone in the kidneys?
it increases salt reabsorption in the distal convoluted tubule and collects thereby increasing water reabsorption and blood volume which in turn increases blood pressure. it also increases potassium and hydrogen ion excretion.
What is the role of the kidneys?
Regulation of Water and Electrolyte Balance, Excretion of Metabolic Waste, Excretion of hormones and drugs, Regulation of Arterial Blood Pressure, Regulation of Red Blood Cell Production, Regulation of Vitamin D Production, and Metabolism
What happens if more sodium is reabsorbed?
if more sodium is reabsorbed, water will follow, the blood volume will increase, and therefore BP increases
What is the diff b/w ADH and aldosterone?
ADH governs only water reabsorption and thus lowers blood osmolarity. aldosterone causes both salt and water reabsorption and does not change blood osmolarity
What is the role of ADH/vasopressin in the kidneys?
ADH (peptide) hormone is made by the hypothalamus and released by the posterior pituitary in response to high blood osmolarity and low blood volume. it increases water reabsorption in the collecting ducts, which results in an increased blood volume and pressure, and decreases blood osmolarity
What happens at the renal cortex?
where filtration and reabsorption occur - proximal and distal convoluted tubule are found here
What is oncotic pressure?
osmotic pressure due to dissolved proteins
What happens at the glomerulus?
(ball of capillaries), where plasma filtration occurs
What happens at the vaso recta?
(second capillaries) reabsorption of vital nutrients
What are the 2 sphincter muscles of the bladder?
internal urethral - consists of smooth muscle and is under involuntary PNS control
external urethral - consists of skeletal muscles and is under voluntary control
What controls the detrusor muscle?
the detrusor muscles line the bladder and are under parasympathetic control
What are the 3 processes of solute movement in the kidneys?
Filtration - the moment of solutes from the blood to filtrate at the Bowmen’s capsule at the rate determined by sterling forces
Secretion - the movement of solutes from the blood to filtrate anywhere other than the bowman’s capsule
Reabsorption - the movement of solutes from the filtrate to blood
What is the function of the proximal convoluted tubule segment of the nephron?
bulk reabsorption of glucose, amino acids, soluble vitamins, salts, and water. It is also the site of the secretion of hydrogen and potassium ions, ammonia, and urea
What is the function of the Ascending loop of Henle segment of the nephron?
salt reabsorption and allowing dilution of the ruined in the diluting segment in the outer medulla
What is the function of the descending loop of Henle segment of the nephron?
water reabsorption using the medullary concentration gradient. the Vasa recta and nephron flow in opposite directions, creating a countercurrent multiplier system that allows maximal reabsorption of water
What is the function of the distal convoluted tubule segment of the nephron?
responsive to aldosterone and is the site of salt reabsorption and water. It is also the site of the secretion of hydrogen and potassium ions, ammonia, and urea
What is the function of the collecting duct segment of the nephron?
site for urine concentration. responsible to both ADH and aldosterone and has variable permeability, which allows reabsorption of the right amount of water depending on the body’s need
What are the 3 layers of the skin?
hypodermis (subcutaneous layer), dermis, and epidermis
What are the 5 layers of the epidermis?
- stratum basale - contains stem cells that proliferate to form keratinocytes
- stratum spinosum
- stratum granulosum
- stratum lucidum - contains dead keratinocytes
- stratum corneum - formed by many thin layers of keratinocytes
What is the role of Langerhans cells?
Langerhans cells are specialized macrophages that serve as antigen-presenting cells in the skin
What are the 2 layers of the dermis?
papillary -contains loose connective tissue
reticular - consists of dense connective tissue
What cells are contained in the dermis?
Merkle cells - deep pressure and texture senses
free nerve endings for pain sensation
Meissner’s corpuscles - light touch senses
Ruffini endings - stretch
Pacinian corpuscles - deep pressure and vibration
What cells are contained in the hypodermis?
fat and connective tissue, and connects the skin to the rest of the body
What is the role of the skin?
thermoregulation, and prevents dehydration and salt loss from the body
What Is the mechanism for warming?
arrector pili muscles contract, causing hairs to stand on end, trapping a layer of warm air around the skin, vasoconstriction, occurs, the body shivers, and the insulated by fat
What is the flow of excretion?
Bowmn’s space –> PCT –> Descending limb of the loop of Henle –> ascending limb of the loop of Henle
–> DCT –> collecting duct –> renal pelvis –> ureter
–> bladder –> urethra
What are the vessels in the renal vasculature?
renal artery –> afferent arteriole –> glomerulus –> efferent arteriole –> vasa recta –> renal vein
Where can proteins be found in the urine?
only in the glomerulus because other nephron structures cannot reabsorb large proteins if they pass through the glomerulus
What is the function of the nephrons?
to make urine that is hypertonic to the blood
What substance is excreted in high volumes in the urine when the pH of blood is high?
bicarbonate ions
