Hormonal coordination in human

Question 1

What does the endocrine system consist of?

Answer 1

glands that secrete chemicals called hormones directly into the bloodstream

Question 2

What are hormones?

Answer 2

chemical messengers that are carried in the blood to target organ where they produce an effect

Question 3

What do hormones control?

Answer 3

things in organs and cells that need constant adjustment

Question 4

What are hormones secreted by?

Answer 4

endocrine glands

Question 5

Whats the difference between the duration and speed of the endocrine system and the nervous system>

Answer 5

the endocrine system is slower and the effects lasts for longer

Question 6

what is the pituitary gland and what does it do?

Answer 6

master gland - it secretes several hormones in response to body conditions

Question 7

What is blood glucose concentration monitored and controlled by?

what does this thing release?

Answer 7

the pancreas, it releases insuln and glucagon

Question 8

How does the body process glucose?

Answer 8

1) Glucose comes into the blood from the gut

2) the normal metabolism of cells removes glucose from the blood

3) Vigorous exercises removes much more glucose from the blood

4) excess glucose can be stored as glycogen in the liver and in the muscles

5) the levels of glucose must be kept steady

Question 9

What happens when the levels of glucose rise?

Answer 9

1) Pancrease releases more insulin

2) causes glucose to move from the blood to cells

3) in liver and muscle cells, excess glucose is converted to glycogen for storage

Question 10

What happens when the levels of glucose decrease?

Answer 10

1) Pancrease releases glucagon

2) Glucagon stimulates glycogen to be converted into glucose and released into the blood

Question 11

What is Type 1 diabetes?

Answer 11

a disorder that:

• is caused by the pancreas failing to produce sufficient insulin
• results in uncontrolled high blood glucose levels
• normally treated with insulin injections ( this makes sure the glucose is removed from the blood quickly once the food has been digested)
• this is genetic

Question 12

What is Type 2 diabetes?

• what is it caused by, risk factor, how is it controlled

Answer 12

a disorder that:

• is caused by the body cells no longer responding to insulin
• obesity is a risk
• controlled with a carbohydrate-controlled diet and regular exercise

Question 13

When and where is adrenaline produced?

Answer 13

produced by the adrenal glands (just above the kidneys)

released in response to a stressful or scary situation

Question 14

How is adrenaline produced and what does it do to the body?

Answer 14

the brain detects fear or stress and sends nervous impulses to the adrenal glands, which responds by secreting adrenaline

It increases the heart rate and boosts the delivery of oxygen and glucose to the brain and muscles, preparing the body for ‘flight or fight’.

Question 15

Where is thyroxine produced and why is it important?

Answer 15

released by the thyroid gland (in the neck)

stimulates the basal metabolic rate, important for growth and development

Question 16

How is thyroxine produced and how is it controlled?

Answer 16

Thyroxine is released in response to the thyroid-stimulating hormone (TSH), which is released from the pituitary gland

when an increase in thyroxine is detected, the release of TSH is inhibited till it gets back to normal

Question 17

Give three ways in which excess water is removed from the body.

Answer 17

Excess water is removed from the body:

Via the lungs during exhalation

From the skin as sweat

By the kidneys in urine

Question 18

Give 2 ways in which excess ions and urea are removed from the body.

Answer 18

Excess ions and urea are removed from the body…

from the skin as sweat
from the kidneys in the urine

Question 19

What do the kidneys do?

Answer 19

regulate the balance of water and ions in the body

The kidneys produce urine by filtration of the blood and selective reabsorption of useful substances such as glucose, some ions and water.

Question 20

How is Urea produced?

Answer 20

• the digestion of proteins from food results in excess amino acids
• in the liver, these excess amino acids are converted to ammonia = deamination
• The nitrogen component of proteins is toxic, so it is immediately converted to urea in the liver
• Urea is then transported to the kidneys where it’s filtered out of the blood and excreted from the body in the urine

Question 21

What’s in urine

Answer 21

water, ion and urea

Question 22

Describe the relationship between the kidneys and associated structures in the body

• renal artery/vein
• ureter
• sphincester

Answer 22

Each kidney receives blood from the aorta via a renal artery. The blood is filtered to remove urea, excess water and salts. The filtered blood is returned to the vena cava via a renal vein.

The mixture of substances removed from the blood plasma (the filtrate) is called urine. It passes down a ureter to the bladder, where it is stored.

A sphincter muscle at the base of the bladder controls the release of urine through the urethra.

Question 23

What is a nephron and describe its structure

Answer 23

• structural part of a kidney

Each nephron consists of a glomerulus, renal capsule and renal tubule. Capillaries leaving the glomerulus are closely associated with the tubule.

Question 24

What happens to the body cells if the concentration of the blood changes?

Answer 24

they will lose or gin too much water by osmosis

Question 25

What happens when the water content is too low? (too concentrated)

Answer 25

- a receptor in the brain detects water content too low - the coordination centre in the brain receives the information and coordinates a response - Pituitary gland releases ADH into the bloodstream - ADH passes in the blood to kidney tubules - This causes more water to be reabsorbed back into the blood

Question 26

Describe what happens to body cells when the water concentration is too high

Answer 26

too much water will enter the cell via osmosis and the cell will burst = hypotonic

Question 27

Describe what happens to body cells when the water concentration is too low

Answer 27

water will leave via osmosis and the cell will shrivel = hypertonic

Question 28

What happens if your kidney's don't work properly?

Answer 28

Waste substances build up and you lose the ability to control the levels of ions and water in your body resulting in death

Question 29

What are the two different types of treatment for kidney failure

Answer 29

kidney transplant and dialysis

Question 30

dialysis machine : what does it do? Why does it have to be done regularly?

Answer 30

it takes over the role of the kidneys, it is used to remove waste products from the blood three times a week it has to be done regularly to keep the concentration of dissolved substances in the blood at normal levels, and to remove waste products

Question 31

Describe the overall structure of the kidney and their relevance in helping the kidney do its job

Answer 31

A kidney is composed of three main regions: the cortex, medulla and pelvis. Blood enters a kidney through a renal artery. This divides into arterioles and capillaries in the cortex. Each capillary becomes knotted to form a glomerulus, which is surrounded by a Bowman’s capsule. This leads to a convoluted tubule. The proximal convoluted tubule passes down into the medulla, where it forms the loop of Henle, returning to a distal convoluted tubule in the cortex again. The tubule joins a collecting duct, which passes down through the medulla into the pelvis of the kidney.

Question 32

Describe ultrafiltration

Answer 32

Blood arrives at the renal artery at high pressure and enters the glomerlus (capillaries) in the Bowman’s capsule. High pressure forces the small molecules such as urea, water, glucose, amino acids and mineral ions out of the blood to the Bowman’s capsule. Large molecules such as protein and blood cells stay in the blood.

Question 33

Describe selective reabsorption

Answer 33

The nephron first filters the small molecules from the blood plasma. It then moves useful substances, such as glucose, mineral ions and water out of the filtrate and back into the bloodstream by active transport. All the glucose is reabsorbed, however, only sufficient water and ions are reabsorbed to maintain the balance between them. This mostly happens in the proximal convoluted tubule water is mostly absored at the loop of henle

Question 34

How does a dialysis machine work?

Answer 34

In a dialysis machine, the person's blood flows between partially permeable membrane surrounded by dialysis fluid. It's permeable to things like ions and waste substances but not big molecules like proteins (just like the membranes in the kidney)

Question 35

What are the advantages of a dialysis machine?

Answer 35

- Dialysis fluid has the same concentration of dissolved ions and glucose as healthy blood so useful dissolved ions won't be lost from the blood during dialysis - only waste substances and excess ions and waste diffuse across the barrier - can buy a patient with kidney failure valuable time until a donor organ is found

Question 36

What are the disadvantages of a dialysis machine?

Answer 36

- have to have it 3x a week - each session is 3-4 hours - may cause blood clots or infections - not a pleasant experience - expensive for the NHS to run

Question 37

What are the advantages of a Kidney transplant?

Answer 37

- cheaper than dialysis in the long run - can put an end to the hours patients have to spend on dialysis

Question 38

What are the disadvantages of a Kidney transplant?

Answer 38

- small risk to the person donating a kidney -donor kidney can be rejected by person's immune system - Patient has to take immunosuppressant drugs for the rest of their life = increases risk of infection - long waiting lists

Question 39

Explain what happens when the liver breaks down haemoglobin in red blood cells

Answer 39

The product is a yellow/green bile pigment called bilirubin. This is excreted with bile into the small intestine. Bilirubin is expelled with faeces.

Question 40

what does sweat contain

Answer 40

sodium chloride and traces of urea dissolved in water

Question 41

Describe urination

Answer 41

Salts not needed by the body, along with urea and uric acid, continue along the tubule into a collecting duct in the medulla. The collecting duct delivers the filtrate to the pelvis of the kidney, where the fluid (urine) passes into a ureter to transfer it to the bladder for storage. Urine is retained in the bladder by a sphincter muscle at its base. When the sphincter muscle relaxes, the muscle wall of the bladder contracts to expel the urine (a process called urination) through the urethra.