Homeostasis Flashcards
Components of Urine of a Healthy Person
Salts
Water
Uric Acids
Urea
Glucagon and Raising Blood Glucose
Alpha cells in the pancreas produce glucagon in response to low blood sugar to raise it
Glucagon prevents the conversion of glucose into fatty acids for storage, breaks down glycogen into glucose, and decreases respiration
Thermoregulation Mechanisms when Hot
Sweating: Sweat glands produce sweat that evaporates from the skin thus removing heat through evaporation
Vasodilation: Blood vessels in the skin dilate, which allows for more blood to flow to remove heat
Hairs Relax: Hairs lie flat against the skin, minimizing trapped air and promoting heat loss
Metabolic Rate Decreases: Thyroid gland produces less thyroxin which reduces body’s metabolic activity
Selective Reabsorption
The Proximal Convoluted Tubule is the longest part of the nephron, and over 80% of the filtrate is reabsorbed into the tissue fluid and then to the blood thus leaving the kidney
Process of Ultrafiltration
Since the afferent arteriole is much larger than the efferent, it builds up hydrostatic pressure inside the capillaries, forcing fluids to pass from the blood through the fenestrated capillaries in the glomerulus into the Bowman’s Capsule
The liquid then drains through the Bowman’s Capsule to the Proximal Convoluted Tubule
Large molecules like blood cells and proteins can’t pass through the Bowman’s Capsule, therefore have to return to the blood through the efferent arteriole
The liquid that passes through the Bowman’s Capsule is called Glomerular Filtrate, and includes water, salts and amino acids
Brain in Sleep, Vigorous Exercise, and Wakeful Rest
Sleep: High to support essential functions such as memory
Vigorous Exercise: High to meet the high metabolic demands and maintain cognitive function and coordination
Wakeful Rest: High to sustain cognitive function and consciousness while the body is awake and alert
Negative Feedback
When an organism does the opposite of a change to bring the organism’s conditions back to normal to maintain equilibrium
Loop of Henle
Has an ascending and descending limb
Ascending limb transports NaCl by diffusion and active transport out of the loop into the tissue fluid which increases solute concentration in tissue fluid and decreases solute concentration of the fluid in ascending limb itself
Descending limb has water move into the tissue fluid by osmosis, and NaCl diffuse from the tissue fluid into the loop
Fluid becomes more concentrated at the bottom of the loop, and animals that need to conserve water have very long loops of Henle to allow for more water to be reabsorbed
If Urine Contains ___?
Glucose, diabetes
Proteins, kidney disease or damage
Blood Cells, bacterial infection
Thermoregulation Process
Thermoreceptors in skin detect change in temperature and send signal to hypothalamus, the brain’s thermostat
Hypothalamus interprets the signals and determines whether temperature is rising or falling, and decides if the body cools down or heats up
Factors that Affect Volume and Concentration of Urine
Water intake
Temperature
Sugar or Salt Intake
Environmental Conditions
Degree / Amount of Exercise
Skeletal Muscles in Sleep, Vigorous Exercise, and Wakeful Rest
Sleep: Low due to inactivity
Vigorous Exercise: High to meet the increased demand for oxygen and nutrients required for muscle contraction
Wakeful Rest: Moderate, reflecting lower activity level compared to exercise
Structure of the Cells of the Tubules Adapted for Reabsorption
Microvilli: Increase the surface area of the inner surface
Pumps: Actively transport glucose and amino acids against their concentration gradient
Mitochondria: Provides ATP needed for Selective Reabsorption
Receptors, Control Centers, and Effectors
Receptors: Detect stimuli
Control Centers: Transfer information between different parts of the body
Effector: The muscle and glands that bring out a response
Osmoregulation
The process where the body regulates the solute concentration in its fluid by maintaining balance between water and electrolytes
