Biology Flashcards
Structure of the eye and functions
the eye is a sense organ
It contains receptor cells that are sensitive to
light: rod cells
Colour: cone cells
Cornea
Transparent lens that refracted light as it enters the eye
iris
Controls how much light enters the pupil
lens
Transparent disc that can change shape to focus light onto the retina
Retina
Contains light receptor cells - rods detect light intensity and cones detect colour
Optic nerve
sensory neurone that carries impulses between the eye and the brain
pupil
Hole that allows light to enter the eye
the pupil reflex
The muscles of the iris control how much light enters the eye, depending on whether we are in a bright or dim environment.
What are the two types of receptor cells in the retina
rods which are sensitive to dim light
Cones which distinguish between different colours in bright light
Hormone
a chemical substance produced by a gland and carried by the blood, which alters the activity of one or more specific target organs
what are the glands that produce hormones in animals called
endocrine system
Growth hormone
regulates growth and physical development. It can stimulate growth in almost all of your tissues. Its primary targets are bones and muscles
Thyroid-stimulating hormone
This hormoneactivates your thyroid to release thyroid hormones. Your thyroid gland and the hormones it produces are crucial for metabolism.
Adrenocorticotropic hormone.
This hormonestimulates your adrenal glands to produce cortisol and other hormones.
Follicle-stimulating hormone.
is involved with oestrogen secretion and the growth of egg cells in women. It’s also important for sperm cell production in men
Luteinising hormone
is involved in the production of estrogen in women and testosterone in men.
Adrenaline is known as
the fight or flight hormone as it isproduced in situations where the body may be in danger
What does adrenaline do to the body
Increasing blood glucose concentrationforincreased respiration in muscle cells
Increasing pulse rateandbreathing rateso glucose and oxygen can bedelivered to muscle cells, and carbon dioxide taken away, from muscles cellsmore quickly
Diverting blood flow towards musclesand away from non-essential parts of the body such as the alimentary canal; again to ensure the reactants of respiration are as available as possible
Dilating pupilsto allow as much light as possible to reach the retina somore information can be sent to the brain
Problems that can be caused by malnutrition
constipiation
Coronary heart disease
obesity
Which tissue in the stem does liquid travel through to reach the petals?
xylem
Describe the correct sequence for the movement of blood in a mammal
body -> heart -> lungs -> heart
Describe species
a group of organisms that reproduce to produce fertile offspring
Two features of most reptiles
Fertilisation is internal
Lay eggs
Transpiration is the loss of water vapour from plant leaves by _______
Evaporation
the effect of humidity on the rate of transpiration
As humidity increases the rate of transpiration decreases
State the name of vessels that transport water in plants
xylem
State the name of the cells where water enter a plant
root hair cell
Two other parts of the large intestine
Colon, Rectum