Homeostasis

Question 1

Homeostasis

Answer 1

Keeping internal conditions stable within limits

Question 2

Negative Feedback

Answer 2

When an organism does the opposite of a change to bring the organism’s conditions back to normal to maintain equilibrium

Question 3

Receptors, Control Centers, and Effectors

Answer 3

Receptors: Detect stimuli

Control Centers: Transfer information between different parts of the body

Effector: The muscle and glands that bring out a response

Question 4

Insulin and Lowering Blood Glucose

Answer 4

Beta cells in the pancreas produce insulin in response to high blood sugar to lower it

Insulin converts glucose into fatty acids for storage, stores glucose as glycogen, and increases respiration

Question 5

Glucagon and Raising Blood Glucose

Answer 5

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

Question 5

Type 1 VS Type 2 Diabetes

Answer 5

Insulin is not being produced
Pancreas doesn’t respond to insulin

Genetic and environmental factors
Age and diet and genetics

During childhood
During adulthood

No proven cure
Lifestyle modifications such as diet and exercise

Requires insulin injections to regulate blood sugar
Medication and managing lifestyle

Question 6

Thermoregulation Process

Answer 6

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

Question 7

Thermoregulation Mechanisms when Hot

Answer 7

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

Question 8

Thermoregulation Mechanisms when Cold

Answer 8

Shivering: Muscles contract to generate heat

Vasoconstriction: Blood vessels in the skin constrict which reduces blood flow to minimize heat loss

Hairs Contract: Hairs stand, trapping a layer of insulating air next to the skin (Goosebumps)

Metabolic Rate Increases: Thyroid gland produces more thyroxin which increases body’s metabolic activity

Question 9

Osmoregulation

Answer 9

The process where the body regulates the solute concentration in its fluid by maintaining balance between water and electrolytes

Question 10

Excretory Organs

Answer 10

Kidneys: Excrete excess water

Liver: Converts excess amino acids into urea

Lungs: Gets rid of carbon dioxide and water vapor

Sweat Glands: Excretes water, salts, and toxins

Question 11

Kidney Structure

Answer 11

Blood enters through the renal artery and drained through the renal vein

Surrounded by a tough capsule, outer region is cortex and inner is medulla

Central region is the pelvis which leads to the ureter

Question 12

Afferent and Efferent Arterioles

Answer 12

Blood arrives to the nephron in the afferent arterioles and delivers to network of capillaries called a glomerulus in a cup shaped structure called Bowman’s Capsule

Blood leaves the glomerulus in the efferent arteriole which is narrower than the afferent arteriole

Question 13

What Separates Glomerulus and Lumen

Answer 13

Endothelium: 1 cell thick with more gaps than other capillaries

Basement Membrane: Made of network of collagen and glycoprotein

Podocytes: Cells with tiny finger like projections that make up the lining of the Bowman’s capsule that wrap around the blood vessels of the glomerulus

Question 14

Process of Ultrafiltration

Answer 14

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

Question 15

Conditions for Ultrafiltration

Answer 15

Hydrostatic Pressure due to the difference in diameter between afferent and efferent arteriole

Basement Membrane to restrict the passage of large molecules such as blood cells and proteins

Question 16

Selective Reabsorption

Answer 16

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

Question 17

Structure of the Cells of the Tubules Adapted for Reabsorption

Answer 17

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

Question 18

Differences in Blood Concentrations between Renal Artery and Vein

Answer 18

Wastes: High in artery and low in vein as it’s excreted in urine

Oxygen: High in artery and low in vein as it’s used in cell respiration by kidney tissue

Glucose: High in artery and low in vein as it’s used in cell respiration by kidney tissue

Drugs / Toxins: High in artery and low in vein as it’s excreted in urine

Carbon Dioxide: Low in artery and high in vein as it’s produced by cell respiration and excretion of kidney cells

Ions: Vary in both as it depends on amount of water reabsorbed in the collecting duct in response to ADH

Question 19

Loop of Henle

Answer 19

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

Question 20

Collecting Duct

Answer 20

After loop of Henle, the fluid moves to the collecting duct where the high solute concentration establishes an osmotic gradient. Water in the filtrate can passively diffuse out into the blood thus making the urine more concentrated

The water leaves through aquaporins which are controlled by ADH, which allows for the amount of water in urine to be controlled

Question 21

Components of Urine of a Healthy Person

Answer 21

Salts

Water

Uric Acids

Urea

Question 22

If Urine Contains ___?

Answer 22

Glucose, diabetes

Proteins, kidney disease or damage

Blood Cells, bacterial infection

Question 23

Response to Thirst

Answer 23

Osmoreceptor cells in the hypothalamus detect the high osmolarity in the blood plasma and produce ADH, which gets released from the posterior pituitary

The ADH binds to receptors in the plasma membrane of cells in the collecting ducts which causes the cell to transport vesicles containing aquaporins towards the membrane and fuse with it, thus inserting aquaporins into the membrane

With more aquaporins embedded, more aquaporin channels open and increases the amount of water to passively diffuse by osmosis into the medulla, which produces small columns of concentrated urine

Question 24

Response to Hydrated

Answer 24

ADH levels decrease, thus the walls of the collecting ducts allow less water to pass into the blood thus less water is conserved by the body, which produces dilute urine

Question 25

Importance of Osmoregulation in Animals

Answer 25

If water uptake is excessive, hydrostatic pressure can stretch the plasma membrane to the point of bursting

If water loss is excessive, the cell will shrink and die as water is an essential for the cell’s cytoplasm

Question 26

Factors that Affect Volume and Concentration of Urine

Answer 26

Water intake

Temperature

Sugar or Salt Intake

Environmental Conditions

Degree / Amount of Exercise

Question 27

Skeletal Muscles in Sleep, Vigorous Exercise, and Wakeful Rest

Answer 27

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

Question 28

Gut in Sleep, Vigorous Exercise, and Wakeful Rest

Answer 28

Sleep: Low as body’s metabolic activity decreases

Vigorous Exercise: Low as blood is redirected to other vital organs involved in exercise

Wakeful Rest: Moderate to support ongoing digestive processes and nutrient absorption from food intake

Question 29

Brain in Sleep, Vigorous Exercise, and Wakeful Rest

Answer 29

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

Question 30

Kidney in Sleep, Vigorous Exercise, and Wakeful Rest

Answer 30

Sleep: Moderate to maintain renal function

Vigorous Exercise: Moderate and decreased slightly as blood is redirected to active tissues

Wakeful Rest: Moderate to ensure filtration and regulation of blood composition