Homeostasis Flashcards
What is homeostasis?
The steady-state balance in the internal environment of an animal’s body that are regulated by a variety of control systems
What are the components of control systems?
- Monitor (sensors in the body detect when an organ is out of balance)
- Coordinating System (received information from monitor and initials signal to regulator)
- Regulator (affect the change)
What is negative and positive feedback?
Negative: when monitor detects change in variable, signal is sent to coordinating system causing regulator to counter the change
Positive: system reinforces the change, less common
What are the 3 types of regulation in the human body?
Thermoregulation
Osmoregulation
pH
What is thermoregulation? Why is it important?
Maintenance of body temperature within a range that allows them to function efficiently
Importance because proteins change their conformation with temperature
What is the monitor for thermoregulation?
- Sensors in brain detect rise in body temperature
- Thermoreceptors in skin detect drop in external temperature
What is the coordinating system for thermoregulation?
Primative brain/brain stem: the hypothalamas
What are the regulators for thermoregulation? What do they do?
TOO HOT: dissipate heat
Sweat glands: evaporation cools skin
Vasodilation: increase heat loss by radiation (blood vessels)
TOO COLD: reduce heat loss/make heat
Vasoconstriction: conserve heat (blood vessels)
Piloerector muscles: causes hair to stand up to trap warm air
Brown fat: make heat by cellular respiration
Muscles: cause shivering, producing heat
What is the role of the kidney in homeostasis?
- Water balance
- Maintains solute concentrations
- Eliminates N wastes (toxic by products)
- Regulates pH ([H+])
What is the function of the kidney (how does it carry out its role)?
- Filter blood: movement of fluids from blood into nephron
- Reabsorb valuable solutes: active and passive transport return substances to blood
- Secrete solutes: everything left over is excreted
Answer for the glomerulus and Bowman’s capsule:
- Substance transported?
- Method of transport?
Plasma minus proteins
Bulk flow
Answer for proximal tubule:
- Substance transported?
- Method of transport?
Ions, water, glucose, amino acids (100% retrieved)
Active + passive transport
Answer for descending/ascending loop of Henle:
- Substance transported?
- Method of transport?
H2O/NaCl
Passive transport/Passive + active transport
Answer for the distal tubule:
- Substance transported?
- Method of transport?
Ions
Active + passive transport
Answer for the collecting duct:
- Substance transported?
- Method of transport?
Wastes
None
How is urine formed?
- Selectively permeable glomerulus and pressure forces small ions with fluid into Bowman’s capsule
- This fluid enters proximal tubule using the active and passive transport of ions to bring in the fluid, substances are reabsorbed to capillaries
- Fluid enters loop of Henle which is permeable to water on descending side and salt to the ascending
- Water diffuses in, then salt is actively transported out
- Distal tubule fine tunes concentration and in the presence of ADH (increases permeability of H2O), more water is absorbed
- Collecting tubule actively reabsorbs NaCl and alters concentration of water
Where is urine formed? What is the components of this system and their function?
Nephron (functional unit of kidney)
- Cortex: outer layer of kidney (protects)
- Medulla: inner layer of kidney (has concentration gradient)
- Renal Pelvis: hollow cavity (connects kidney to ureter)
- Ureter: tube (sends urine to bladder)
- Urethra: tube exits bladder (urination)
- Afferent Arteriole: incoming (supply blood to glomerulus)
- Efferent Arteriole: outgoing arterial (supply blood to peritubular capilaries)
- Pertitubular Capillaries: capillary network (collects reabsorbed material)
- Glomerulus: leaky capillaries (filters blood)
- Bowman’s Capsule: folded structure (collects filtrate or filtered left over)
- Proximal Tubule: folded tube (reabsorb 85% of filtrate)
- Loop of Henle: U shaped tube (reabsorb H2O and NaCl)
- Distal Tubule: folded tube (reabsorb or secrete based of hormonal regulation)
- Collecting Duct: branched tube (collect urine, sent to pelvis, fine tune urine concentration)
