Excretion

Question 1

What is homeostasis?

Answer 1

The maintenance of a constant internal environment in an organism (temperature, fluid balance, pH)

Homeostasis is crucial for the stability of biological systems.

Question 2

What are ectotherms?

Answer 2

Organisms that gain or lose heat from/to their environment, also known as cold-blooded (e.g., fish, frogs, snakes)

Ectothermic animals depend on external sources to regulate their body temperature.

Question 3

What are endotherms?

Answer 3

Organisms that generate their own heat from metabolic reactions, also known as warm-blooded (e.g., birds, mammals, humans)

Endothermic animals can maintain a stable body temperature regardless of the environment.

Question 4

What is the primary function of the lungs in excretion?

Answer 4

Excrete carbon dioxide and water vapor

Lungs play a vital role in gas exchange and maintaining acid-base balance.

Question 5

What does the skin excrete?

Answer 5

Water and salt in sweat

Skin excretion helps in thermoregulation and maintaining osmotic balance.

Question 6

What do kidneys excrete?

Answer 6

Water, salts, and urea in the form of urine

Kidneys are crucial for waste elimination and fluid balance.

Question 7

What comprises the urinary system?

Answer 7

2 kidneys, 2 ureters, bladder, and urethra

The urinary system is essential for filtering blood and removing waste.

Question 8

Where are the kidneys located?

Answer 8

In the lower back

Kidneys are retroperitoneal organs, meaning they are situated behind the peritoneum.

Question 9

What are the three parts of the kidney?

Answer 9

Pelvis, medulla, and cortex

Each part has distinct functions in the filtration and excretion processes.

Question 10

How does blood arrive at the kidneys for filtration?

Answer 10

Via the renal artery, branching from the aorta

This pathway is crucial for delivering blood that needs to be filtered.

Question 11

Fill in the blank: The kidneys are fist-sized _______ organs.

Answer 11

[bean-shaped]

Their shape is important for their structure and function.

Question 12

What is the primary function of the kidneys related to fluid balance?

Answer 12

Osmoregulation

The kidneys control the amount of water and salt released.

Question 13

How do the kidneys help maintain blood pH?

Answer 13

By producing urine that is more or less acidic

This allows the pH of the blood to stay at 7.4.

Question 14

What are the three processes involved in urine production?

Answer 14

Filtration, reabsorption, and secretion

These processes are essential for urine formation.

Question 15

Where is urine produced within the kidney?

Answer 15

In the renal tubules located in both the cortex and medulla

The renal tubules are key structures for urine formation.

Question 16

What is the role of the glomerulus in kidney function?

Answer 16

Filtration of blood

It is a network of capillaries where blood enters through the afferent arteriole.

Question 17

What type of blood vessel carries blood into the glomerulus?

Answer 17

Afferent arteriole

Blood leaves the glomerulus through the efferent arteriole.

Question 18

What happens to small molecules during filtration in the glomerulus?

Answer 18

They are forced out into Bowman’s capsule

This includes glucose, amino acids, vitamins, urea, water, and salts.

Question 19

Fill in the blank: The __________ artery supplies blood to the kidneys.

Answer 19

Renal

The renal artery branches off from the abdominal aorta.

Question 20

True or False: The efferent arteriole carries blood away from the glomerulus.

Answer 20

True

This vessel carries filtered blood from the glomerulus.

Question 21

What is the function of Bowman’s capsule?

Answer 21

Holds the filtrate that has been filtered from the blood

It is the first part of the nephron.

Question 22

List the components forced out during glomerular filtration.

Answer 22

• Glucose
• Amino acids
• Vitamins
• Urea
• Water
• Salts

These components are essential for bodily functions and are part of urine.

Question 23

What is the first part of the nephron involved in excretion?

Answer 23

The glomerulus

The glomerulus is a network of capillaries involved in the filtration of blood.

Question 24

What substances cannot fit through the pores in the capillaries and remain in the blood?

Answer 24

Proteins

Proteins are generally too large to pass through the filtration barrier of the glomerulus.

Question 25

What facilitates the process of filtration in the nephron?

Answer 25

Higher than normal blood pressure ## Footnote The difference in diameters of the afferent and efferent arterioles creates this pressure.

Question 26

What is absorbed in the proximal convoluted tubule (PCT)?

Answer 26

* Water * Salts * Glucose * Amino acids * Vitamins ## Footnote These substances are absorbed by osmosis, diffusion, and active transport.

Question 27

What are the characteristics of the proximal convoluted tubule (PCT)?

Answer 27

* One cell thick * Numerous villi to increase surface area * Many mitochondria for energy ## Footnote These adaptations facilitate efficient reabsorption.

Question 28

Where are water and salts reabsorbed in the nephron?

Answer 28

Loop of Henle ## Footnote The Loop of Henle plays a crucial role in concentrating urine.

Question 29

What is the role of the distal convoluted tubule (DCT)?

Answer 29

Involvement in further reabsorption of water ## Footnote The DCT fine-tunes the composition of urine.

Question 30

Fill in the blank: Some water can be reabsorbed from the collecting duct by _______.

Answer 30

Osmosis ## Footnote Osmosis allows water to move from areas of low concentration to high concentration.

Question 31

What is the resulting liquid called after reabsorption in the nephron?

Answer 31

Urine ## Footnote Urine is the final product of filtration and reabsorption processes in the kidneys.

Question 32

Through which structures is urine transported to the bladder?

Answer 32

Collecting ducts and ureters ## Footnote The collecting ducts lead to the ureters, which transport urine to the bladder.

Question 33

True or False: The proximal convoluted tubule is involved in the secretion of waste products.

Answer 33

False ## Footnote The PCT primarily focuses on reabsorption rather than secretion.

Question 34

What is the composition of glomerular filtrate compared to urine?

Answer 34

Filtrate (Glomerular) has more water than urine as most is reabsorbed. ## Footnote Filtrate contains useful substances, glucose, amino acids, etc., that are not normally present in urine.

Question 35

What happens when we drink too little or sweat too much?

Answer 35

The salt concentration of plasma may rise and blood volume drops.

Question 36

How do receptors in the brain respond to changes in blood volume?

Answer 36

Receptors in the brain sense this change and cause the pituitary gland to release Anti-Diuretic Hormone (ADH), also called Vasopressin.

Question 37

What effect does ADH have on the kidneys?

Answer 37

ADH travels in the bloodstream to the kidneys, where it causes the DCT and collecting duct to become more permeable and lose water by osmosis to the surrounding tissues.

Question 38

What happens to ADH secretion when blood volume returns to normal?

Answer 38

As soon as the blood volume returns to normal, secretion of ADH ceases.

Question 39

What is the effect of ADH on urine production?

Answer 39

ADH will cause a smaller volume of urine to be produced.

Question 40

What are the components of skin anatomy related to sweating?

Answer 40

Hair, sweat pores, nerves, sweat glands, and tissue.

Question 41

What is one function of the skin related to pathogens?

Answer 41

Prevents the entry of pathogens ## Footnote This is a crucial protective function of the skin.

Question 42

What substance does the skin produce to protect against UV light?

Answer 42

Melanin ## Footnote Melanin absorbs UV radiation, reducing the risk of skin damage.

Question 43

What is the role of sebum produced by sebaceous glands?

Answer 43

Prevents skin from drying out ## Footnote Sebum provides a protective barrier and moisturizes the skin.

Question 44

What vitamin is produced by the skin after exposure to sunlight?

Answer 44

Vitamin D ## Footnote Vitamin D is essential for calcium absorption and bone health.

Question 45

What is the function of sweat glands in the skin?

Answer 45

Act as organs for excretion ## Footnote Sweat helps remove waste products from the body.

Question 46

What type of organ is the skin classified as?

Answer 46

Sense organ ## Footnote The skin contains receptors for touch, pressure, temperature, and pain.

Question 47

What happens to sweat in warm conditions?

Answer 47

Evaporates, cooling the body ## Footnote Evaporation of sweat is a key mechanism for thermoregulation.

Question 48

What is piloerection?

Answer 48

Causes hairs to stand up ## Footnote This process helps trap air underneath the hairs, providing insulation.

Question 49

What occurs to blood vessels in the skin during cold conditions?

Answer 49

Vasoconstriction reduces blood flow ## Footnote This helps retain heat in the body.

Question 50

Fill in the blank: The skin contains many receptors for _______.

Answer 50

nerve endings ## Footnote These receptors are essential for sensing the environment.

Question 51

What happens to blood vessels in the skin when it is warm?

Answer 51

Dilate, turning the skin red ## Footnote This process increases blood flow to the skin to release heat.

Question 52

True or False: The skin plays a role in temperature regulation.

Answer 52

True ## Footnote The skin helps maintain homeostasis through various mechanisms.

Question 53

What is the result of rapid contractions and relaxing of muscles in the skin?

Answer 53

Produces heat to raise body temperatures ## Footnote This is part of the body's response to cold environments.