Biology Chapter 10: Homeostasis (3 Stars) Flashcards
The _______ system serves many functions, including the regulation of blood pressure, blood osmolarity, acid–base balance, and removal of nitrogenous wastes.
excretory
The _____ produces urine, which dumps into the ureter at the renal pelvis. Urine is then collected in the bladder until it is excreted through the urethra.
kidney
The kidney contains a cortex and a ______. Each kidney has a hilum, which contains a renal artery, renal vein, and ureter.
medulla
The kidney contains a portal system with #____ capillary beds in series.
two
Blood from the _____ artery flows into afferent arterioles, which form glomeruli in Bowman’s capsule (the first capillary bed).
renal
Blood then flows through the _____ arteriole to the vasa recta, which surround the nephron (the second capillary bed), before leaving the kidney through the renal vein.
efferent
The bladder has a muscular lining known as the _____ muscle, which is under parasympathetic control. It also has two muscular sphincters.
detrusor
The internal ______ sphincter consists of smooth muscle and is under involuntary (parasympathetic) control.
urethral
The external urethral sphincter consists of ______ muscle and is under voluntary control.
skeletal
The kidney participates in _____ movement through three processes:
solute
Filtration is the movement of solutes from blood to filtrate at _____. The direction and rate of filtration is determined by Starling forces, which account for the hydrostatic and oncotic pressure differentials between the glomerulus and Bowman’s space.
Bowman’s capsule.
_____ is the movement of solutes from blood to filtrate anywhere other than Bowman’s capsule.
Secretion
____ is the movement of solutes from filtrate to blood.
Reabsorption
Each segment of the _____ has a specific function.
nephron
The proximal convoluted tubule (PCT) is the site of bulk ______ of glucose, amino acids, soluble vitamins, salt, and water. It is also the site of secretion for hydrogen ions, potassium ions, ammonia, and urea.
reabsorption
The descending limb of the loop of Henle is permeable to water but not _______; therefore, as the filtrate moves into the more osmotically concentrated renal medulla, water is reabsorbed from the filtrate. The vasa recta and nephron flow in opposite directions, creating a countercurrent multiplier system that allows maximal reabsorption of water.
salt
The ascending limb of the loop of Henle is permeable to salt but not water; therefore, salt is reabsorbed both passively and actively. The _____ segment is in the outer medulla; because salt is actively reabsorbed in this site, the filtrate actually becomes hypotonic compared to the blood.
diluting
The distal convoluted tubule (DCT) is responsive to ______ and is a site of salt reabsorption and waste product excretion, like the PCT.
aldosterone
The ______ is responsive to both aldosterone and antidiuretic hormone and has variable permeability, which allows reabsorption of the right amount of water depending on the body’s needs.
collecting duct
The kidney is under hormonal control. When blood pressure (and volume) are low, #____ different hormonal systems are activated.
two
Aldosterone is a steroid hormone regulated by the renin–angiotensin– aldosterone system that increases ____ reabsorption in the distal convoluted tubule and collecting duct, thereby increasing water reabsorption. This results in an increased blood volume (and pressure), but no change in blood osmolarity.
sodium
Antidiuretic hormone (ADH or vasopressin) is a peptide hormone synthesized by the hypothalamus and released by the posterior pituitary. Its release is stimulated not only by low blood volume but also by high blood osmolarity. It increases the permeability of the collecting duct to water, increasing water reabsorption. This results in an increased blood volume (and pressure) and a _____ blood osmolarity.
decreased
The kidney can regulate ____ by selective reabsorption or secretion of bicarbonate or hydrogen ions. Skin
pH
The skin acts as a ______ protecting us from the elements and invasion by pathogens.
barrier
The ____ is composed of three major layers: the hypodermis (subcutaneous layer), dermis, and epidermis.
skin
The epidermis is composed of five layers: the stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum. The stratum basale contains ____ cells that proliferate to form keratinocytes. Keratinocyte nuclei are lost in the stratum granulosum, and many thin layers form in the stratum corneum.
stem
_______ produce melanin, which protects the skin from DNA damage caused by ultraviolet radiation; melanin is passed to keratinocytes.
Melanocytes
______ cells are special macrophages that serve as antigen-presenting cells in the skin.
Langerhans
The dermis is composed of two layers: the papillary layer and the _________
reticular layer.
Many sensory cells are located in the ______including Merkel cells (deep pressure and texture), free nerve endings (pain), Meissner’s corpuscles (light touch), Ruffini endings (stretch), and Pacinian corpuscles (deep pressure and vibration).
dermis,
The _______ contains fat and connective tissue and connects the skin to the rest of the body.
hypodermis
The skin is important for ________, or the maintenance of a constant internal temperature.
thermoregulation
Cooling mechanisms include _______, which absorbs heat from the body through evaporation of water from sweat, and vasodilation. Sweat glands are innervated by postganglionic cholinergic sympathetic neurons.
sweating
Warming mechanisms include piloerection, in which arrector pili muscles _____, causing hairs to stand on end (trapping a layer of warmed air around the skin), vasoconstriction, shivering, and insulation provided by fat.
contract
The _____ also prevents dehydration and salt loss from the body
skin
