B1.2 Flashcards
Why does water content in the body need to be controled
Too little chemical reactions in cells won’t be able to take place and substances won’t be able to dissolve into the blood
Too much can cause swelling and high blood pressure
Why does temperature need to be controlled in the body
Needs to be kept at the optimum temperature for enzymes to increase rate of reactions in the body
What is the process of keeping the internal environment stable called
Homeostasis
What is a gland
A part of the body that creates a substance and then releases it
What is the control of water in the body called
Osmoregulation
How do we lose water
Through sweat and our breath
How is water regulated in the body
Too much and the kidneys produce lower conçentration urine, has more water in it
Too little kidneys produce higher concentration of urine with less water and tells the brain to make you thirsty
What is the control of the temperature of our body called
Thermoregulation
What is our ideal temp
37C
What is the hypothalamus and what does it do
Small part of the brain that measures external temperature through the info it receives from nerve endings in the dermis part of the skin. It also measures internal temperature of the body through the temp of the blood
What is the dermis part of the skin
The layer of skin beneath the epidermis (outer most layer) and contains nerves endings, blood vessels and hair roots
How is temperature controlled in our body if too cold
If too cold, hypothalamus causes muscles to shiver which releases energy and heat. Erector mussels in the dermis contract to make hairs stand up, this helps other mammals keep warm as it traps the warm air, however it doesn’t help us much
Vasoconstriction occurs in the blood vessels near the skin
If too hot
Sweating occurs and when the sweat evaporates, some of the heat is transferred from the skin to the surroundings.
Vasodilation occurs on capillaries in the dermis
What is vasodilation and vasoconstriction
Vasodilation is where the capillaries near the surface of the skin widen to increase blood flow so heat is transferred onto the skin from the blood and sweat removes that heat.
Vasoconstriction is where the capillaries near the surface of the skin constrict to reduce blood flow and reduce blood loss
How is thermoregulation an example of negative feedback
If too hot, body tries to reduce temp, if too cold, body tries to heat up.
What are sense organs and what do they all contain
Organs that detect changes inside and outside the body and they all contain receptor çells that detect a stimulus
How does the brain know about changes
Receptor cells detect the stimulus. They then create elctrical signals called impulses and they are sent to the brain which then sends impulses to other parts of the body to make something happen
What do impulses travel along and what is this process called
Travel along neutrons and this is called neurotransmission
What is the structure of a sensory neurone and how does it work
Dendrites on the end of dendrons detect impulses from receptor cells. The impulses travels along the dendrons and into the cell body, from there it travels through the axons and into the axon endings. Axon endings then pass on the signal to others dendrites
What is a nerve
A bunch of neutrons packed together
What is the CNS and what is it made of
Central nervous system and is made of the brain and spinal chord. The cns controls your body