Hormones

Question 1

What is a gland?

Answer 1

A gland is an organ that releases or secrets a substance

Question 2

What is an exocrine gland?

Answer 2

Exocrine glands secrete their products through a tube or duct

Question 3

What are endocrine glands?

Answer 3

Endocrine glands are ductless and instead the hormones are secreted into the blood vessels that pass through the gland

Question 4

What are hormones?

Answer 4

-Hormones are chemical messengers sent in the blood
-They are carried in the blood plasma to other parts of the body, but only affect target cells
-Hormones control things in organs that need constant adjustment
-Hormones are produced in various glands, they travel quite slowly and tend to have relatively long-lasting effects
(Chemical messages that control processes in our bodies, including homeostasis)

Question 5

What are the characteristics of the nervous system?

Answer 5

1. Nerve impulses travel fast and usually have an ‘instant’ effect
2. The response is usually short lived
3. The impulses act on a very precise area and so have a very localised effect.
4. Only animals
5. Nerve impulses transmitted through nerve cells (electrical messages travel along neurones) (although chemical messages travel across the synapses)

Question 6

What are the characteristics of the endocrine system?

Answer 6

1. Hormones travel more slowly and generally take longer to act, minutes rather than milliseconds
2. The response is usually longer-lasting
3. Hormones can have widespread effects on different organs (although they only act on particular tissues or organs if the cells have the correct receptors)
4. Animals and plants
5. Hormones transmitted through the bloodstream (chemical messages travel in blood) - only chemical messages are involved

Question 7

Describe ADH (anti-diuretic hormone)

Answer 7

• Found: pituitary gland
• Function: controls the water content of the blood by its effect on kidneys
• Effect: increases the permeability of the kidney tubules to water

Question 8

Describe Adrenaline

Answer 8

• Found: adrenal glands (on top of the kidneys)
• Function: prepares the body for stressful or physically active situation, a ‘flight or fight’ response,
• Effect: increases heart rate to send more oxygen to muscles for respiration, breathing rate so more oxygen into body and remove excess CO2, blood flow to muscles and blood sugar levels

Question 9

Describe Insulin and Glucagon

Answer 9

• Found: Pancreas

- Function: lowers blood glucose and raises blood glucose levels

Question 10

Describe Testosterone

Answer 10

• Found: testes
• Function: main male sex hormone, and controls the development of male secondary sexual characteristics involved in sperm production as well e.g. facial hair

Question 11

Describe Oestrogen

Answer 11

• Found: ovaries
• Function: main female sex hormone, and controls the development of female secondary sexual characteristics e.g. widening of the hips

Question 12

Describe Progesterone

Answer 12

• Found: ovaries

- Function: supports pregnancy, regulates menstrual cycle and maintains the lining of the uterus

Question 13

Describe some of the hormones found in the pituitary gland

Answer 13

• LH (luteinising hormone) stimulates egg release (ovulation) in females and testosterone production in males
• FSH (follicle stimulating hormone) stimulates egg development and oestrogen secretion in females and sperm production in males
• GH (growth hormone) speeds up the rate of growth and development in children

Question 14

What does adrenaline do?

Answer 14

Prepares an animal’s body for action, and so the muscles need a good supply of oxygen and glucose for respiration and so adrenaline produces several changes in the body that cause this to happen as well as other changes to prepare for flight of light

Question 15

What does adrenaline actually do?

Answer 15

• Breathing rate increases and breaths become deeper, taking more oxygen into the body
• The heart beats faster, sending more blood to the muscles, so that they receive more glucose and oxygen for respiration
• Blood is diverted away form the intestines and into the muscles
• In the liver stored carbs are changed into glucose and released into the blood. The muscle cells absorb more glucose and use it for respiration
• The pupils dilate, increasing visual sensitivity to movement
• Body hair stands on end, making the animal look larger to the enemy
• Mental awareness is increased, so reactions are faster

Question 16

How does insulin affect blood sugar level?

Answer 16

When blood glucose is too high:
1. detected by pancreas
2. INSULIN is secreted 
3. Which converts Glucose into Glycogen 
4. This is then stored in the liver
When blood glucose is too low:
1. detected by the pancreas
2. GLUCAGON is secreted
3. which converts the Glycogen into Glucose
4. This is then released into the blood

Question 17

What happens when someone has diabetes?

Answer 17

• People with diabetes do not produce enough insulin. When they eat food, the glucose levels in their blood cannot be reduced.
• Diabetics sometimes have to inject insulin into their blood and they have to be careful of their diet

Question 18

Which organ monitors blood sugar concentration?

Answer 18

Pancreas

Question 19

How is diabetes detected by doctors?

Answer 19

• There is glucose in the urine

- Another symptom is constant thirst