WorksheetsBiology: Homeostasis, Neurones & Reflex actions
Total questions: 15
Worksheet time: 8mins
What is Homeostasis?
The regulation of the internal conditions of a cell or organism
Glands that secrete hormones directly into the bloodstream
The biological term for sleeping
Many conditions are controlled in the body, they include the following three.....
Body temperature
Blood glucose concentration
Water levels
Volume of blood
Homeostasis uses automatic control systems. This may include, nervous responses (involving the nervous system) and chemical responses (involving hormones). All control systems have three main parts which are......
Receptors: These are cells that detect stimuli (changes in the environment.)
Coordination centres: such as the brain, spinal cord, pancreas. These receive information from receptors and process it.
Effectors: such as muscles or glands. These bring about the responses needed.
Homeostasis does two things which are.......
maintains optimal conditions for enzyme action and all cell functions
involves responses to changes in the internal or external conditions
Sometimes the control mechanisms in homeostasis are described as "negative feedback mechanisms". Describe why?
For example, if water content increases, the control mechanism decreases it again.
For example, if water content decreases, the control mechansim increases it again.
Similarly, Homeostasis works to adjust body temperature and blood glucose concentration levels.
What are neurones?
Cells in the nervous system
Cells in the endocrine system
Cells in the circulatory system
There are 3 types of Neurones, what are they? What do they do?
Sensory neurones - which carry electrical impulses from receptors to the central nervous system (CNS)
Relay neurones - which are in the CNS and carry sensory neurones to motor neurones
Motor neurones - which carry impulses from the CNS to EFFECTORS, such as muscles and glands.
All types of neurone have what?
An AXON
Dendrites
Dendrons
Sensory neurones have something that motor neurones & relay neurones don't have....what is it?
Dendron
An axon
Dendrites
Explain how the cell is adapted to its function in the nervous system
The AXON is long so it can transmit impulses over long distances.
The DENDRITES can receive impulses from other neurones,
The AXON terminal can connect with EFFECTORS (such as muscles and glands).
The fatty myelin sheath insulates the AXON from other neurones and stops the impulses being randomly transmitted to other neurones.
The electrical impulses can jump quickly from one gap to another.
The Central Nervous System is more commonly called 2 things, what are they?
Brain
Spinal Cord
Heart
Lungs
REFLEX actions do NOT involve the conscious part of the brain which means they are two things, what are they?
Automatic
Rapid
Slow
Manual
Reflex actions are important for two reasons, what are they?
They control basic functions such as breathing
They help to avoid danger and harm
It means they must happen when we are asleep
It means we can jump up quickly
The point where two neurones meet is called a.....?
SYNAPSE
AXON
DENDRON
Electrical nerve impulses cannot cross the gap between neurones and so the signal is transmitted with NEURO TRANSMITTERS. This process does 3 things, what are they?
Works in one direction only
Allows one nerve impulse to produce impulses in several other neurones
Slower than nerve impulses
