Biology: Chapter 10: Homeostasis Flashcards
What is the excretory system
regulation of blood pressure, blood osmolarity, acid-base balance, and removal of nitrogenous wastes
What is the pathway of the excretory system
kidney -> renal pelvis -> ureter -> bladder -> urethra
what is the structure of the kidney
cortex –> outer layer
medulla –> inner layer
hilum –> renal artery, renal vein, and ureter
what is the renal portal system
1 ) blood from the renal artery flows into the afferent arterioles into the glomerulus
2) Blood flows from the glomerulus into the efferent arteriole to the vasa recta then the renal vein
what is the dutrusor muscle
muscular lining of the bladder under parasympathetic control; contains the internal sphincter muscle (smooth muscle) and the external sphincter muscle (skeletal muscle)
what are the three processes of the kidney
filtration, secretion, reabsorption
what is filtration
movement of solutes from the blood to the filtrate at the Bowman’s capsule; movement determined by starling forces (hydrostatic and oncotic pressure)
what is secretion
movement of solutes from blood to filtrate anywhere other than the bowman capsule (PCT/DCT)
what is reabsorption
movement of solutes from filtrate to the blood
what is the Proximal convoluted tubule
site of bulk reabsorption of glucose, amino acids, soluble vitamins, salt, and water; site of secretion for hydrogen ions, potassium ions, ammonia, and urea
what is the descending limb of the loop of henle
permeable to water but not salt causing reabsorption of water as limb descends into more osmotically concentrated medulla
what is the counter current multiplier system
vasa recta and nephron flow in opposite directions that allows for maximal reabsorption of water
what is the ascending limb of the loop of henle
permeable to salt but not water leading to passive and active salt reabsorption; filtrate becomes hypertonic compared to the blood
what is the distal convoluted tubule
responsive to aldosterone and is site of salt reabsorption and waste production
what is the collecting duct
responsive to both aldosterone and ADH for variable permeability allowing for the right absorption of water depending on the body’s needs
what is aldosterone
steroid hormone regulated by the renin-angiotensin-aldosterone system for increased sodium reabsorption = water retension
what is ADH
peptide hormone synthesized in the hypothalamus and released in the posterior pituitary; increases permeability of collecting duct = water retention
how does the kidney regulate pH
selective reabsorption or secretion of bicarbonate/hydrogen ions
what are the skin layers
epidermis, dermis, hypodermis
what is the epidermis
composed of five layers: Stratum basale, Stratum spinosum, Stratum granulosum, Stratum lucidum, Stratum corneum
what is special about stratum basale
contains stem cells that proliferate to form keratinocytes
what are melanocytes
produce melanin which protects the skin from DNA damage caused by UV radiation
what are langerhan cells
special macrophages that serve as antigen presenting cells in the skin
what are the layers in the dermis
papillary layer and the reticular layer
where are sensory nerves located
dermis
what are merkel cells
deep pressure and texture
what are meissner corpuscles
light touch
what are ruffini endings
stretch
what are pacinian corpuscles
deep pressure and vibration
what are free nerve endings
pain
what is the hypodermis
contains fat and connective tissue and connects the skin to the rest of the body
what are the cooling mechanisms of the skin
sweating to draw heat from the body through evaporation of water from sweat and vasodilation
what are the warming mechanisms of the skin
piloerection where arrector pili muscles contract causing hairs to stand on end to trap a warm layer of air around the skin; vasoconstriction; shivering; and insulation provided by fat
