B7 Biology

Question 1

what is the definition of a hormone ?

Answer 1

a chemical messenger released from the endocrine glands, which travels in the blood plasma which affect target cells

Question 2

which hormones are released from which endocrine glands ?

Answer 2

Oestrogen - ovaries
LH - pituitary gland
FSH - pituitary gland
Adrenalin - adrenal gland

Question 3

Adrenalin prepares the body for ‘fight or flight’ by?

Answer 3

1) increased heart beat (muscle cells contract more rapidly which allows faster delivery of oxegen and glucose to the muscles

2) increased blood pressure due to number 1

3) increased blood flow too the muscles which allows higher reaction of respiration.

4) higher glucose conversion in the liver

Question 4

what is thyroxine?

Answer 4

thyroxine is produced from the thyroid gland which stimulates the metabolic rate.
it controls how quickly the body can convert oxegen and food to use as energy.

Question 5

the control of thyroxine levels uses 3 hormones.

Answer 5

TRF - released from the hypothalamus - Acts on the pituitary gland and causes the release of TSH

TSH - released from the pituitary gland and acts on the thyroid gland causing T4 to be released.

T4 - released from the thyroid gland and regulates metabolism

Question 6

what is homeostasis ?

Answer 6

homeostasis is the maintenance of a controlled internal enviroment e.g. - keeping optimum tempreture

Question 7

what is negative feed back ?

Answer 7

negative feedback relates to Homeostasis. when something changes in homeostasis (from optimum) negative feedback kicks in to use corrective mechanisms to get it back to optimum conditions

Question 8

menstrual cycle

Answer 8

day 1 ) menstruation - release of uterus lining and egg cell

day 5) new egg cell (ovum) begins to develop and uterus lining thickens

Day 14) ovulation occurs and the egg cell is released into the oviduct

day 15 -20 ) the ovum moves down the oviduct, and uterus lining continues to thicken (where pregnancy is most likely to occur

day 21-28) continued move of egg cell down the oviduct towards the uterus.

Question 9

role of hormones

Answer 9

Oestrogen - secreted by the ovaries into the blood. Repairs and thickens the uterus lining. Stimulates release of LH (positive feedback). Inhibits production of FSH (negative feedback).

PROGESTERONE- secreted by ovaries into blood (and later corpus luteum and placenta). Has a role in maintaining the uterus lining. Inhibits FSH and LH release (_negative feedback)

LH (LUTEINISING HORMONE): released by the pituitary gland. Triggers ovulation.

FSH (FOLLICLE STIMULATING HORMONE): stimulates growth and maturation of egg follicle (containing an ovum).

Question 10

what is IVF and clomifene therapy?

Answer 10

In Virto Fertilisation
when a sperm and egg cell is combined in a lab to help couples get preganant

(2 separate things)

The women take a drug called CLOMIFENE. This causes more FSH and LH to be released by the body which stimulates egg cell development and ovulation

Question 11

how does insulin help control the blood glucose concertation in your body?

Answer 11

insulin helps by increasing glucose absorption from the blood, converting excess glucose to glycogen.

Question 12

how is blood glucose concentration regulated by glucagon?

Answer 12

If the blood glucose level is too low, the pancreas releases the hormone glucagon. This travels to the liver in the blood and causes the break-down of glycogen into glucose.

Question 13

causes and control of type 1 diabetes

Answer 13

causes - pancreas no longer releases insulin which means low amount of glycogen

control - take insulin injections

Question 14

equation for BMI =

Answer 14

mass (kg) / height (metres2)

Question 15

causes and control of type 2 diabetes

Answer 15

causes:
Obesity , fat surrounds the organs and blocks receptors which means
Insulin cant bind to the receptors

Sometimes people dont have to be obease they can just have a bad diet and still
Build up lots of fats and colagen around the organs

control:

Lose the weight, exercise more and control diet

Question 16

what is thermoregulation?

Answer 16

Thermoregulation is the control of Body temperature to keep the core body temperature as close to 37oC, if temperature is too high or low enzyme activity will be affected.

Question 17

what is the Hypothalamus’ role in thermoregulation ?

Answer 17

The Hypothalamus in the brain detects temperature changes (stimuli) in the brain and blood and bring about corrective responses – this is another example of Homeostasis

Question 18

what is the dermis? and what is its role in thermoregulation?

Answer 18

the dermis is the layer of flesh under the outer layer of skin.

its contains tempreture receptors and sweat glands so when you are too hot its releases sweat to cool you down

Question 19

what is the epidermis? and what role does it have in

Answer 19

the epidermis is the outer layer of skin where sweat sits and evaporates.

Question 20

the diffrent cell shapes after osmosis

Answer 20

cell that is about to burst : lysed

cell that has average water potential : normal

cell that dosent have enough water potential : shrivelled

Question 21

name the key points of the excretion system

Answer 21

1) renal artery brings blood and renal vein takes blood away.

2) ureter drains urine to the bladder and the bladder holds the urine

3) urethra takes urine out the body

Question 22

what is dialysis ?

Answer 22

dialysis is where blood is removed from a blood vessel, it is then taken into a dialyzer where it is cleaned with fresh dialysate and then pumped back into a blood vessel