B3.2 spec

Question 1

define what a hormone is

Answer 1

a chemical messenger

Question 2

how are hormones released?

Answer 2

secreted by endocrine glands (organs that makes hormones that are released directly into the blood and travel to tissues and organs all over the body)

Question 3

how are hormones transported around the body?

Answer 3

through the bloodstream

Question 4

explain the role of adrenaline in the body

Answer 4

• responsible for ‘fight or flight’ response for survival
• A HORMONE

Question 5

where is adrenaline released from?
(and where is it situated)

Answer 5

the adrenal gland
- above each kidney
2 OF THEM

Question 6

effects of adrenaline?

Answer 6

• increases heart + breathing rate
• dilates pupils
• diverts blood from digestion to limbs
• increase respiration rate

Question 7

explain thyroxine in terms of its negative feedback loop (ie. when levels are too low) (6 points)

Answer 7

• hypothalamus detects thyroxine levels are too low
• pituitary gland releases TSH (thyroid stimulating hormone)
• which stimulates thyroid gland to release thyroxine
• hypothalamus detects energy levels are ‘normal’
• TSH stops being released from pituitary gland
• so thyroid gland stops releasing thyroxine

Question 8

what is the role of thyroxine in the body?

Answer 8

• controls metabolic rate (how quickly chemical store converted to energy for body to use)

Question 9

in general, describe the 5 stages in a negative feedback loop

Answer 9

1) conditions change
2) receptor detects change
3) corrective mechanism initiated
4) back to original level
5) corrective mechanisms switched off

Question 10

reason for a negative feedback loop?

Answer 10

• to maintain homeostasis in the body
  (ie. keep internal conditions constant)

Question 11

what is the role of testosterone in males?

(in terms of human reproduction)

Answer 11

stimulating sperm production

Question 12

what secondary characteristics are caused by an increase in testosterone levels? (3)

Answer 12

• increase in height
• body + pubic hair growth
• enlargement of penis and testes

Question 13

where is testosterone and oestrogen produced?

Answer 13

T - testes
O - ovaries

Question 14

difference between nerve impulses and hormones (in terms of where they travel)

Answer 14

nerve impulses - only to specific parts of body

hormones - all around the body

Question 15

why do all hormones not affect all organs? (2)

Answer 15

• as only TARGET organs respond
• hormones only bind to specific receptors in target organs

Question 16

where are receptors for hormones found?

Answer 16

on the membrane/cytoplasm of cells in target organs

Question 17

where is progesterone made in the body?

Answer 17

in ovaries (produced by corpus luteum)

Question 18

what is the acronym to remember the interactions of hormones in the menstrual cycle?

Answer 18

FOLP

fsh -> oes + oes STOPS -> fsh

o -> l

LOOK at mia’s digram on b3 folder (11b)

Question 19

what do LH and FSH do?

Answer 19

FSH - stimulates one egg to mature/ripen
LH - stimulates follicle to release egg

Question 20

when do progesterone levels fall?

Answer 20

after day 21

Question 21

state 3 examples of non-hormonal contraception
(and explain how each works)

Answer 21

condom - prevents sperm entering vagina

diaphragm/cervical cap - into vagina + covers cervix, prevents sperm entering uterus

IUD - releases copper + kills sperm in uterus/fallopian tubes

Question 22

what is the downside of using a diaphragm or cervical cap?

Answer 22

you must use spermicide with it

Question 23

state 3 examples of hormonal contraception
(and explain how each one works)

Answer 23

combined pill - oestrogen + progesterone
( oestrogen prevents FSH from being released, and therefore no ovulation, progesterone thickens mucus in cervix so sperm no enter uterus + stops LH being released so egg does not enter oviduct

progesterone only pill - thickens mucus in cervix + stops ovulation 60% of the time (less side effects like nausea)

IUS - inserted into uterus
(same effect on body as progesterone-only pill)

Question 24

how does IVF work? (4)

Answer 24

• LH and FSH given to stimulate eggs to mature
• eggs collected + fertilized
• egg developed into embryo
• embryo implanted into uterus

Question 25

how are hormones used to treat infertility?

Answer 25

• FSH and LH given to mother for eggs to mature to be collected

Question 26

causes of infertility in women (2)

Answer 26

women - lack of mature eggs
- ovaries cannot release egg

Question 27

causes of infertility in men (2)

Answer 27

men - blocked sperm ducts
- not enough sperm cells