Homeostasis Flashcards
Detrusor muscle
a muscle that forms a layer of the wall of the bladder.
Internal urethral sphincter
smooth muscle, contracted in normal state, involuntary control
External urethral sphincter
skeletal muscle, voluntary control
Micturition reflex
parasympathetic neurons firing causing detrusor muscle to contract, causing internal sphincter to relax
Kidney function processes
- Filtration
- Secretion
- Reabsorption
Starling forces in filtration by kidney
- Hydrostatic pressure in glomerulus»_space; Bowman’s space
- Osmolarity of blood > Bowman’s Space
- Hydrostatic pressure»_space; oncotic pressure - net flow from blood to Bowman’s capsule
Nephron: what is absorbed and secreted in proximal convoluted tubule (PCT)
- Reabsorption of: 70% of Na+, as well as Cl-, H2O, amino acids, glucose, water-soluble vitamins. Via vasa recta into interstitium.
- Site of secretion of H+, K+, NH3, and urea
Nephron: what is absorbed and secreted in loop of Henle
- Descending limb: only permeable to water, with increasing osmolarity as go down.
- Ascending limb: only permeable to salts, impermeable to water
Countercurrent multiplier system
Flow of filtrate through the loop of Henle in opposite direction from the flow of blood through the vasa recta. Filtrate constantly being exposed to hypertonic blood in descending limb, ensuring max water reabsorption.
Diluting segment: what type of cells lines it, how the filtrate becomes
Thickening of loop of Henle at transition from inner to outer medulla.
- Cells lining the tube larger, larger amt of mitochondria, which enable active transport of ions.
- Filtrate becomes hypotonic compared to interstitium - the only portion that urine is more dilute than blood. Important during overhydration.
Distal convoluted tubule: what it responds to, what happens to urine
Responds to aldosterone (promotes Na reabsorption). Water follows the sodium, concentrating the urine
Collecting duct: what it responds to
Responsive to both aldosterone & ADH
What the filtrate mostly contains as it exits collecting duct
urea, uric acid, and excess ions
Functions of Excretory System
- Control BP
- Control blood osmolarity
- Control acid-base balance
Skin/ Integument
- Hypodermis
- Dermis
- Epidermis
Hypodermis: what it is (layer of ___), what it has (what it’s composed of)
- Layer of connective tissue
2. Has fat and fibrous tissue
Layers of dermis (deepest to top, what it contains)
- Reticular layer: sweat glands, blood vessels, hair follicle origins
- Papillary layer: loose connective tissue
Location of most sensory receptors (Meissner’s corpuscles, Merkel discs, Free nerve endings, etc.)
Dermis
Layers of strata (deepest to top, what it contains)
Come, Let’s Get Sun Burnt
- Stratum basale: contains stem cells & important for proliferation of keratinocytes (produce keratin)
- Stratum spinosum: connected to each other, site of Langerhans cells
- Stratum granulosum: keratinocytes die, lose nuclei
- Stratum lucidum: only in hairless, thick skin - nearly transparent
- Stratum corneum: has dozens of layers of flattened keratinocytes, forming barrier that prevents invasion by pathogens & helps to prevent loss of fluids & salt
Calluses
excessive keratin
Melanocytes: where it comes from, where it is, what it produces
From neural crest cells, in stratum basale. Produce melanin
Langerhans cells
macrophages within stratum spinosum, presents antigens to T-cells
Thermoregulation
- Sweating
2. Arrector pili/piloerection
Sweating: what it is controlled by, what it is promoted by, what happens to arterioles
- Controlled by ANS
- Promoted by postganglionic sympathetic neurons that utilize Ach
- Arteriolar vasodilation also occurs
Arrector pilli / piloerection
Trap layer of heated air near the skin.
Shivering requires…
ATP
Layers of fat
- White fat = insulates body
2. Brown fat = less efficient in ETC, more heat energy released as fuel
