EQ's Flashcards
Describe how light enters the eye
[4 marks]
The cornea is curved and transparent. It refacts light, which then travels through the pupil, and focuses it onto the lens
The lens then refracts the lightand focuses is onto the retina
Explain how the eye responds to dim light
[3 marks]
The light detectors in the retina (cones and rods) detect the dim light levels
This triggers the reflex arc and electrical impulses are transmitted along neurones
Causing the circular muscle in the iris to relax an the radial muscle in the iris to contract.
This makes the pupil dilated so that a larger volume of light can enter the eye
Lily struggles to read small text in a book when it is close to her face.
Explain what can you conclude about her vision and the structure of her eyes.
[3 marks]
She has hyperopia (lonsightedness)
Means lenses in her eye are too long and thin.
Therefore, they cannot refract light enough, so image is brought into focus behind the retina
Or her eyeballs are too short
so her lenses are too close to the retina.
This means the image is brought into focus behind the retina
Give two ways in which students could improve their investigation on reaction time
[2 marks]
- Repeat the investigation more
- Perform the investigation on several other people
What effect does drinking coffee have on reaction time?
[1 mark]
Caffeine speeds up reaction time
Describe the difference between the function of a receptor and the funtion of an effector.
[4 marks]
A receptor (e.g pain receptors in skin) detect a stimulus which generates elecrtical impulses
An effector (e.g. muscles in arms) convert an impulse into a response action
Give two control variables in the reaction time practical
[2 marks]
- Drop ruler from the same height
- Use the same/dominant hand
Which of the following are examples of reflex actions?
- Jumping in the air to catch a ball
- Raising a hand to protect eyes from bright light
- Releasing saliva when food enters mouth
- Running away from danger
- Withdrawing hand from sharp object
[2 marks]
- Releasing saliva when food enters mouth
- Withdrawing hand from sharp object
They are UNCONSIOUS actions!!!
Alcohol dilates blood vessels in the skin.
Suggest why it is dangerous to drink alcohol between going from hot sauna to a cold swimming pool
[4 marks]
Blood vessel dilation (vasodilation) allows more blood to flow through the capillaries close to the surface of the skin.
This causes heat to be transferred to the surroundings, decreasing body temperature.
If you get too cold, this can lead to hypothermia which is very dangerous
A healthy person without diabetes is given a sugary drink. Their blood glucose levels are monitored and plotted on a graph. The same person is then later given bread. Their blood glucose levels are monitored and put on the same graph to compare to the levels when they drank the sugary drink.
Explain why the blood glucose levels would rise at a slower rate after eating the bread
[3 marks]
Bread contains starch
Starch/Carbohydrates are broken down into glucose by enzymes
This process takes time to release the glucose
So the blood glucose levels rise at a slower rate
During _ _ _ _ _ _ _, reproductive hormones cause secondary sex characteristics to develop
Fill in the blank
Puberty
During puberty, reproductive hormones cause _ _ _ _ _ _ ** ** _ _ characteristics to develop
Fill in the blank
During puberty, hormones cause secondary sex characteristics to develop
Give three examples of secondary sex characteristics
Pubic hair
Wide hips
Breasts
What is the female reproductive hormone?
Oestrogen
Which gland secretes oestrogen?
Ovaries
What is the male reproductive hormone?
Testosterone
Which gland secretes testosterone?
Testes
What is the function of testosterone?
To stimulate the testes to produce sperm
Which four hormones are involved in the mestrual cycle of a woman?
FSH
Oestrogen
LH
Progesterone
How many days does the menstrual cycle last?
28 days
Explain how the hormones FSH, Oestrogen, LH and Progesterone interact in controlling the menstrual cycle
[5 makrs]
- The pituitary gland secretes FSH into the bloodstream. FSH is transmitted along the bloodstream to the ovaries, this causes an egg to mature
- FSH stimulates the secretion of oestrogen from the ovaries into the bloodstream. Oestrogen is transmitted along the bloodstreamto the pituitary gland
- Oestrogen causes the uterus lining to become thick and it inhibits the secretion of FSH from the pituitary gland
- This causes the pituitay gland to secrete LH into the bloodstream. LH is transmitted along the bloodstream and causes the egg to be released from the ovaries (ovulation)
- Ovulation stimulates the secretion of progesterone from the ovaries. Progesterone inhibits the secretion of FSH and LH to prevent more eggs from becoming mature. Progesterone also maintains the thickness of the uterus lining in case a fertilised egg implants
- If the egg is not fertilised this reduced progesterone levels in the blood. This causes the uterus lining and the egg to be released. This causes the woman to have her period
How do hormones travel to their target organs?
They are transmitted through the bloodstream
A woman will be infertile if her body does not release enough FSH.
Explain how injections of FSH could increase the chances of having a baby
[3 marks]
- FSH stimulates the eggs in the ovaries to mature
- So they can be released for fertilisaiton
- It also stimulates the secretion of oestrogen
What is a hormone?
[3 marks]
A chemical messenger
Secreted by an endocrine gland and released into the blood
and affects a target organ
Why are fertility drugs given to some women?
[1 mark]
To help stimulate egg maturation and release to help them have a baby
