CH 13 Flashcards
Homeostasis of High body temperature
Thermoreceptor in skin and hypothalamus detect increase in body temperature
Vasodilation occur
More blood flows under the skin
More heat is loss due to radiation
Erector muscles are less stimulated and relaxed
Fine hair is lowered towards the skin
Promote heat loss as heat is not trapped
Skeletal muscles relax and contract less
Body does not shiver
Sweat glands are stimulated to produce more sweat
Heat is loss as sweat evaporates from the skin
Thyroid gland and Adrenal gland is less stimulated
Secretion of thyroxine and adrenaline is reduced
Metabolic rate decreases
No excess heat is generated
Homeostasis of Low body temperature
Thermoreceptor in hypothalamus and skin detect decrease in body temperature
Vasoconstriction occur
Less blood flows under the skin
Less heat is loss due to radiation
Erector muscles are stimulated and contract
Fine hair stand erect
Prevent heat loss as heat is trapped
Skeletal muscles relax and contract
Body shiver
Sweat glands are not stimulated
No sweating occur
Thyroid gland and Adrenal gland is stimulated
Thyroxine and adrenaline is secreted into the bloodstream
Metabolic rate increases
More heat is generated
Homeostasis of high blood sugar level
Beta cells in pancreatic langerhans is stimulated to secrete insulin into bloodstream
Insulin:
stimulates muscle cells to use glucose through cellular respiration
convert excess glucose into glycogen to be stored in liver
Convert excess glucose to fat in adipose tissue
Homeostasis of low blood sugar level
Alpha cells in pancreatic langerhans is stimulated to secrete glucagon into bloodstream
Glucagon:
convert glycogen to glucose
Homeostasis of partial pressure of blood
Central chemoreceptor detect change of pH value in cerebrospinal fluid and Peripheral chemoreceptor detect change of pH value in blood
Nerves impulse are triggered and sent to respiratory control center and cardiovascular control center in medulla oblongata
Intercostal muscle, cardiac muscles and diaphragm contract and relax quickly
Ventilation rate increase, breathing rate increase, heart rate increases. More carbon dioxide is expelled. More oxygen is inhaled
Homeostasis of high blood pressure
Baroreceptors in aortic body and carotid body is stimulated
Cardiovascular control centre is stimulated
Vasodilation
Smooth muscle relaxes and expands
Less resistance of blood flow
Weaker contraction of cardiac muscles
Heart rate decreases
Homeostasis of low blood pressure
Baroreceptors in aortic body and carotid body is less stimulated
Cardiovascular control centre is less stimulated
Vasoconstriction
Smooth muscle contract and narrows
More resistance to blood flow
Stronger contraction of cardiac muscles
Heart rate Increases
Process of formation of Urine
Ultrafiltration in bowman’s capsule
Blood that enters glomerulus is under high hydrostatic pressure because diameter of efferent arteriole is smaller than afferent arteriole
The pressure forces fluids to pass through the filtration membrane and enter the bowman’s capsule cavity forming glomerular filtrate
Glomerular filtrate has the same composition as blood plasma but does not contain plasma protein, platelets and erythrocytes as the are too large
Reabsorption at proximal convoluted tubule, Loop of Henle and distal convoluted tubule
100% amino acids and glucose is reabsorbed into blood through active transport in PCT
In Loop on henle, water is reabsorbed through osmosis while sodium ions are reabsorbed through active transport
In Distal convoluted tubule, more water, sodium ions and chloride ions are reabsorbed
Secretion
Occurs through simple diffusion and active transport
Hydrogen ion, K+ ions, NH4+ ions, urea and creatinine is secreted into renal tubules
Urine formation
Remaining renal fluid is called urine; flowing down collecting duct
Urine contains water, urea, Sodium Chloride salts uric acid and creatinine
Homeostasis after drinking too much water
Osmotic pressure decreases
Osmoreceptor is less stimulated
Adrenal gland is stimulated to secrete aldosterone into bloodstream
Wall of collecting duct and distal convoluted tubule becomes more permeable to salt
More salt is reabsorbed into blood steam
Urine is produced in large and diluted amounts
Homeostasis after drinking too little water
Osmotic pressure increases
Osmoreceptor is more stimulated
Pituitary gland is stimulated to secrete antidiuretic hormone into bloodstream
Wall of collecting duct and distal convoluted tubule becomes more permeable to water
More water is reabsorbed into blood steam
Urine is produced in small and concentrated amounts
