Physics for You : Plenaries

1
Ch 8
How human bodies respond to change
Neurones
a. Direction of nerve impulse b. Cell body c.
Fatty sheath
d. Axon e. Muscle
2
Ch 8
How human bodies respond to change
Coordination
itch
Can you label this flow chart to represent the
elbow itch example on page 111.
skin receptors
brain and spinal cord
arm muscle
scratch
3
Ch 8
How human bodies respond to change
Synapses

• Synapses are the 1 between nerve cells.
• They act as
• resistors
• junction boxes.

gaps

• They release chemical 2 that 3 across
  the gap.
• The chemical transmitter moves in one direction
  only.
• Some 4.. affect synapses.

transmitters
diffuse
drugs
4
Ch 8
How human bodies respond to change
Reflex arc

• Spinal cord.
• Nerve arrives from along the sensory
  neurone.
• .. neurone.
• Nerve impulse travels to the effector along the
  

impulse
receptor
Relay
Synapse.
motor neurone.
5
Ch 8
How human bodies respond to change
Withdrawal reflex
pain
skin heat sensor
relay neurone in spinal cord
arm shoulder muscles
withdrawal
6
Ch 8
How human bodies respond to change
Your brain
touch
cerebral hemispheres
a
smell
b
taste
c
vision
d
hearing
g
association
h
motor
i
balance
cerebellum
e
automatic
medulla
f
7
Ch 8
How human bodies respond to change
Hormones
action
hormone
gland
thyroxin
thyroid
Controls metabolic rate
blood water balance
pituitary
ADH
insulin and glucagon
pancreas
blood sugar level

• heart rate increases
• blood vessels to muscles widen
• liver releases glucose

adrenalin
adrenal
8
Ch 8
How human bodies respond to change
Ovulation and the menstrual cycle

• What is ovulation?
• The menstrual cycle is controlled by the
  gland.
• What does the oestrogen do in the menstrual
  cycle?
• What does FSH do?
• What does LH do?
• Menstruation is caused by a fall in
  levels.

The release of an egg from the ovary on about day
14.
pituitary
Oestrogen causes the uterus lining to thicken.
FSH causes the ovary follicle to start making an
egg.
LH causes the egg to be released.
progesterone
9
Ch 8
How human bodies respond to change
How hormones control the menstrual cycle

• FSH released
• oestrogen releaseduterus lining thickens
• ovulation
• LH releasedyellow body forms
• progesterone releaseduterus lining thickens
  more

10
Ch 8
How human bodies respond to change
Controlling fertility fertility

• The hormone 1. will stimulate a woman to
  produce eggs.
• This can stimulate fertility, but can result in
  2 births.
• The eggs can be removed and fertilised with 3
  outside the body.
• This is called 4
• The tiny human embryos are then 5 back
  into the mother.

FSH
multiple
sperm
in vitro fertilisation.
implanted
11
Ch 8
How human bodies respond to change
Controlling fertility birth control

• The contraceptive pill contains the hormone
  1..
• This inhibits the production of the hormone 2
  by the 3.. gland.
• This means that no more eggs will be released by
  the 4..

oestrogen.
FSH
pituitary
ovaries.