educake eye Flashcards
Where is the thermoregulatory centre located in the body?
The thermoregulatory centre is located in the brain, which is protected by the skull.
what is the thermoregulatory centre responsible for ?
A region of the brain that is responsible for regulating body temperature to maintain homeostasis.
core body temperature is monitored by the what?
thermoregulatory centre
how does the body help the body to lose heat.
When the core body temperature is higher than normal, the sweat glands in the skin release sweat. This helps the body to lose heat.
glands (2)
- Glands are found in many parts of the body.
- They secrete chemicals in response to a stimulus.
What scientific term is used to describe the process of controlling body temperature?
thermoregulation
in the eye what is the opening that allows light to enter.
The pupil is the opening (aperture) in the iris which allows light to enter the eye.
What is the term for short-sightedness?
This condition is called myopia.
What is the definition for short-sightedness?
A person with short-sightedness can see near objects clearly but cannot focus properly on distant objects
what is the cerebral cortex
The cerebral cortex is highly folded and comprises a large part of the human brain. The cerebral cortex is they grey matter that makes up the outer layer of the cerebrum.
what can short-sightedness can be corrected by
by wearing glasses with concave lenses.
thick lenses
Which part of the eye transmits signals to the brain?
The optic nerve transmits signals from the eye to the brain.
A camera focuses by moving a lens towards or away from a light-sensitive layer. Is this the same or different in the human eye?
“different”
In the human eye, the shape of the lens is changed, rather than the position of the lens.
What stimuli are receptors in the nose and tongue sensitive to?
The nose has receptors sensitive to chemicals in the air and the tongue has receptors sensitive to chemicals in the food we eat.
Receptors in the skin are sensitive to what?
pain, pressure, touch and temperature
True or false? When focusing on distant objects, the shape of the lens in the eye is short and fat.
This is false.
When focusing on distant objects, the shape of the lens in the eye is long and thin. Since the source is far away, the rays will be nearly parallel so require less bending to focus on the retina.
What name is given to the opening at the front of the eye through which light enters?
The pupil is the opening in the iris through which light passes before reaching the lens and being focussed on the retina.
Receptors in the thermoregulatory centre of the brain directly monitor changes in the temperature of the… what?
monitor changes in the temperature of the blood as it flows past them on its way around the body.
Name the part of the eye that connects the ciliary muscle to the lens.
suspensory ligaments
where is temperature receptors located in?
Temperature receptors are located in the brain and the skin.
What type of lens can be used to correct long sight?
Converging (or convex) lenses bring the light rays closer, moving the image location forwards, onto the retina.
what controls the unconscious activities such as breathing rate and heart rate.
medulla oblongata
what is Vasodilation
Vasodilation is a process that occurs in response to the body becoming too hot. The changes it brings about result in more heat being lost from the body and the temperature being returned to normal.
When you need to focus on distant objects your ciliary muscles must be… what?
“relaxed”
When the eye focuses on a distant object the ciliary muscle relaxes allowing the lens to become thinner in shape.
What is the main mechanism that the body uses to cool itself down if it starts to overheat?
sweat
it produces sweat which helps the body to cool down.
Which part of the eye changes shape to increase or decrease the amount of light that enters into the eye?
iris
Is your skin more likely to be flushed red in freezing or hot temperatures?
“hot temperatures” or “hot”
In hot temperatures, human skin appears flushed because of the extra blood supply. In cooler temperatures, skin may be paler or have less of a red tone.
What name is given to the furthest position an object can be from the eye and still be focused clearly?
“far point” or “infinity”
The far point is the furthest point at which an object can be placed and still form a focussed image on the retina.
When the body temperature becomes hot, what dose the hairs on the skin surface do?
lie flat allowing the body to lose heat and cool down.
What organ in the body usually reacts to temperature first?
skin
as the skin contains hot and cold temperature receptors.
you are short-sighted. Where will your lens produce the sharpest image?
In a short-sighted person the image is formed in front of the retina.
what happens if the body temperature is too high?
When the body temperature is too high, changes occur in the blood vessels and sweat producing glands.
where is the image formed if you are long-sighted
The image is being formed behind the retina, so they are long-sighted.
What is the term for long-sightedness?
hyperopia
What name is given to the rapid contraction of the muscles that occurs when the core body temperature is too low?
we shiver as the muscles contract and relax rapidly.
Short sight may be caused by the eyeball being too… what?
“long”
If the eyeball is too long it means that the distance between the lens and the retina is too great so the lens focusses light in front of the retina instead of onto it.
What term is used for the maintenance of conditions inside the body (such as temperature) within a certain optimum range?
homeostasis
If we are too cold, blood is withdrawn from the limbs to where?
When the body becomes too cold, blood is diverted from the limbs to the core to decrease heat loss.
Bringing blood to the surface of the skin helps to cool us down by losing heat through what type of heat transfer?
When the body loses heat through the skin, it does so by a type of heat transfer called radiation.
what is the white outer layer of the eye is called
The white outer layer of the eye is called the sclera or sclerotic. It protects the eye from injury.
In a reflex action, muscles respond by doing what?
When muscles receive impulses from nerves, they contract.
