Homeostasis (chapter 7-8) Flashcards
(37 cards)
7.1 Define Homeostasis
The physiological state of the body in which internal physical and chemical conditions are kept within a range that is suitable for life processes. For example – body temperature is 37˚C, blood pH 7.4 etc
7.1 Define Dynatic Equilibrium
A condition that remains stable within fluctuating limits
7.1 Negative feedback vs Positive feedback + Examples
+Process by which a small effect is amplified i.e. childbirth
-Process by which a mechanism is activated to restore conditions to their original state i.e. testosterone production
7.2 Define Homeotherm + Example
Organism that maintains a stable body temperature regardless of the temperature of the external environment; eg. Humans and birds.
7.2 Define Poikilotherm + Example
Organism whos body temperature varies with, and often matches, the temperature of the external environment; eg. Reptiles, amphibians.
7.2 Define Endotherm
Organism that maintains its body temperature by internal mechanisms
7.2 Define Ectotherm
Organism that maintains its body temperature by absorbing thermal energy from the environment
7.2 Explain the body’s response to heat
Hypothalamus sends signals to sweat glands to initiate sweating, evaporation on skin causes cooling, blood vessels dilate and blood loses heat to skin to cool internal organs
7.2 Explain the body’s response to cold
Hypothalamus sends signals to organs and tissues to increase body temp. Blood vessels constrict to prevent loss of heat to skin. Hair follicle muslces contract to cause goosebumps that trap warm air near skin. Shivering increases metabolism. Brown fat converts chemical energy to heat and is used when prolonged eposure to cold causes hormonal responses
7.3 Define Deamination + Where it occurs
Removal of an amino group from an organic compound. Occurs in
liver
7.3 Name 3 Products of Nitrogenous Waste + When they are released
Ammonia (released during deamination)
Uric acid (released during breakdown of nucleic acids)
Urea (formed by 2 ammonia and carbon dioxide as a way to remove ammonia from the body)
7.4 Explain the Pathway of the Human Urinary System (parts + functions)
Kidney produces urine, ureter transports urine, bladder stores urine, urethera exports urine
7.5 Explain the Pathway of the Formation of Urine (parts + functions)
Kidneys -> nephrons -> bowmans capsule -> glomerulous (filtration) -> proximal convoluted tubule (salts reabsorbed) -> descending loop on henle (water reabsorbed) -> ascending loop of henle (solutes reabsorbed) -> distil convoluted tubule (solutes reabsorbed, secretion) -> collecting duct -> ureter
7.6 Name + Explain 3 functions of kidneys
Water Balance - ADH makes the walls of the distal tubule and collecting ducts more permeable to H2O
Blood PSI - Aldosterone increases N+ and H2O absorption, lowering psi. This triggers Renin to produce Angiotensin to constrict the blood vessels.
pH Balance - Bicarbonate-carbon dioxide buffer system, excess H+ are absorbed by bicarbonate ions.
7.7 (Kidney Disease) Explain Diabetes Mellitus
Low insulin, high blood sugar, reverse osmotic psi, excess sugar in nephron causes water to stay in the nephron and gets lost in urine.
7.7 (Kidney Disease) Explain Diabetes Insipidus
No ADH producing cells, no regulation of water reabsorption, lots of urine (and water) released
7.7 (Kidney Disease) Explain Bright’s
Inflamed nephrons, permeability of nephron affected, large molecules can enter the nephron (no mechanism designed to reabsorb), proteins stuck in nephron cause water to flow into the nephron and increases urine output
7.7 (Kidney Disease) Explain Kidney Stones
Caused by the precipitation of mineral solutes from the blood. The sharp-sided stones can lodge in the renal pelvis or move into the narrow ureter.
7.7 (Kidney Disease) Explain Kidney Transplant + Body’s reaction
A new kidney and ureter are placed into the lower abdomen and surgically attached, the old kidney is only removed if it is infected, and a catheter is inserted to drain urine for the first few days. The immune system will usually attack the new kidney and this is they only downside.
8.1 Define Hormones
Chemical messengers produced by cells in one part of the body (i.e ovaries) that effect cells of another part of the body (i.e breasts).
8.1 Steroid vs Protein hormones (structure, receptor location, hydro-,example)
Steroid vs Protein
4 carbon rings cholesterol / 2-300 amino acid proteins
Nuclear membrane / Cell membrane
Hydrophobic / Hydrophilic
Sex hormones / Growth hormones
8.1 Hypothalamus and pituitary function
The brain monitors bodys internal environment and regulates pituitary gland. Together they control many processes that maintain homeostasis. Hypothalamus secretes releasing factors into the pituitary gland.
8.2 Explain Glucose Regulation + Hormones and what cells they are released by
Insulin - helps High Blood Sugar (produced by beta cells, released when blood sugar increases, causes cells of muscles, liver, and other organs to become permeable to glucose, In the liver glucose is converted into glycogen, the storage form of glucose)
Glucagon - helps Low Blood Sugar (produced by alpha cells, released when blood sugar decreases. Goes to the liver and forces glycogen to become glucose)
8.2 What are the 3 types of diabetes + differences
Type 1 - Juvenile (insulin dependant) 10%
Early degeneration of beta cells. Some, but not enough insulin.
Type 2 - Adult (non-insulin dependant) 90%
Decreased insulin production or ineffective use of insulin produced.
Gestational 2%-10%
Temporary condition during pregnancy that increases the risk of diabetes in both mom and baby.
