Excretory, endocrine and regulation

Question 1

Define excretion

Answer 1

the process of eliminating or expelling waste matter

Question 2

State the organs of the urinary system

Answer 2

Kidney (x2), Ureter (x2), Bladder, Urethra

Question 3

Outline how urine leaves the body from the kidney

Answer 3

The urine from kidneys goes through the ureters into the bladder. The urine then leaves the bladder and out of the body through the urethra.

Question 4

What is a nephron?

Answer 4

the microscopic structural and functional unit of kidney. Its job is to produce urine.

Question 5

Describe the function of the bowman’s capsule

Answer 5

receives the filtered blood (called filtrate) from the glomerulus. This means that substances that exited the glomerulus (e.g. ions, water, glucose, urea) enter the tubule.

Question 6

Describe the function of the proximal convoluted tubule

Answer 6

Reabsorption of certain substances. This means that glucose, specific ions, and amino acids are reabsorbed into capillaries by active transport.

Question 7

Describe the function of the Loop of Henle

Answer 7

Reabsorption of water. This means that the ions are actively pumped out of the tubule.This makes the tissue around the loop of Henle highly concentrated, so water exits via osmosis.

Question 8

Describe the function of the Distal convoluted tubule and collecting duct?

Answer 8

Selective reabsorption of water. This means that the amount of water that is reabsorbed into the bloodstream changes based on the body’s water requirement. For reabsorption to occur, water moves out of the tubule through aquaporins channel proteins and eventually enters the bloodstream via osmosis.

Question 9

What is the main function of the endocrine system?

Answer 9

the endocrine system is part of the body’s communication system and is responsible for regulating the activities of other body systems.

Question 10

What are glands?

Answer 10

Organs that secrete hormones into the bloodstream.

Question 11

What are endocrine hormones?

Answer 11

Chemical signalling molecules secreted by the endocrine glands. Hormones travel in the bloodstream and reach their target cells/organs to bring about changes in the target cells/organs’ activities.

Question 12

State three types of hormones produced by the endocrine system. For each type, provide one example of hormone.

Answer 12

Lipid-based. (Testosterone, estrogen, etc.)
Protein-based. (Insulin, glucagon, ADH, etc.)
Amino acid-based. (Adrenalin, melatonin, thyroxine, etc.)

Question 13

Explain how hormones can only bring about changes/responses in their target cells but not in non-target cells.

Answer 13

Because target cells express receptors that are specific to a given hormone, then they are able to receive the signal/message which causes certain changes/responses in the cells. Non-target cells do not express the specific receptors. Therefore, no responses would occur in the non-target cells, as they can’t receive the signal/message.

Question 14

What is the pituitary gland? Provide one example of hormone secreted by the pituitary gland and state its function.

Answer 14

An organ of the endocrine system that secretes hormones that regulate growth and reproduction.

Growth hormone - stimulates bone and muscle growth for physical development.
ADH - increases water reabsorption in the kidneys.

Question 15

what is the role of pancreas in the endocrine system?

Answer 15

pancreas secretes hormones that regulate blood glucose levels.

Question 16

What does the memory cue “BIGA” tell us?

Answer 16

Beta cells in the pancreas secrete Insulin. Glucagon is secreted by Alpha cells in the pancreas.

Question 17

Give an example of a hormone produced by Adrenal glands. What responses does the chosen hormone elicit in the body?

Answer 17

Adrenalin-
increase the heart rate, dilate pupils, increase the rate of respiration, etc.

Question 18

State the three types of adaptation

Answer 18

Structural (e.g. sweat gland)
Physiological (e.g. sweat being released)
Behavioural (e.g. taking a cool shower)

Question 19

If drawing a feedback loop, state the headings you need to start with

Answer 19

Stimulus
Receptor
Co-ordinator
Effector
Response

(negative feedback written over the arrow between response and stimulus)

Question 20

Define stimulus

Answer 20

Change in the environment

Question 21

State where the receptors for detecting blood temperature are found

Answer 21

Thermoregulatory Centre in the hypothalamus

Question 22

State an effector for the stimulus of blood temperature being too high

Answer 22

Sweat glands releasing sweat. This means that more heat is lost by evaporation.

Vasodilation occurs. This means that there is more blood flow to the surface of the skin and more heat lost by radiation.

Question 23

Define homeostasis

Answer 23

Homeostasis is the maintenance of a constant internal environment, within narrow limits, in the face of external change.