B3 Flashcards
What passes along nerve cells
electrical impulses
What is the gap between two neurones called?
Synapse
What is released across a synapse?
Chemical signals
What is the role of a receptor?
To detect a stimuli
What is the role of a sensory neurone?
To transfer a signal from a receptor to the CNS
What is the role of a motor neurone?
To transfer a signal from the CNS to an effector
What is the role of a relay neurone?
To transfer a signal from a sensory neurone to a motor neurone
What is a reflex?
An automatic response to stimulus
What is the reflex pathway arc
stimulus ➔ receptor ➔ sensory neurone ➔ relay neurone ➔ motor neurone ➔ effector ➔ response
What are the two main types of effectors?
Glands
Muscles
Reflexes are
fast
Automatic
Blinking when you get dust in your eye
Sneezing
are examples of…..
Refelxes
Why are reflexes important?
They protect us from harm
does the reflex arc involve the brain
No it doesnt
What is the role of the effector
The effector then causes a protective response against the stimulus. The effector can be a muscle or a gland.
How many hemispheres is the cerebral cortex split into?
2 halves
hemi means half
What are the roles of the cerebral cortex?
Memory
Interpreting senses like hearing & vision
Consciousness
Emotions
What are the roles of the cerebellum?
Muscle coordination
Balance
What is the medulla is responsible
for coordinating unconscious activities, such as regulating our breathing rate and heart rate
What is the hypothalamus is responsible for?
Regulating our body temperature.
Where in the brain is the medulla found?
In the brain stem
How can scientists find out what parts of the brain do?
Study people with brain damage
Electrically stimulate different parts of the brain
Scan the brain, using CT, PET, MRI, or fMRI scanners
What are the three main reasons treating the brain is so difficult?
There is a huge range of things that can go wrong, from mental illness to infection
It is encased within the skull, so is hard to access
It is very complicated, so hard to target with medications
What is the cornea?
A transparent layer at the front of the eye which refracts light
What does the brain controll?
Complex behaviour
What part of the brain controlls homeostasis
Hypothalamus
What does the pituatry gland produce?
Produces important hormones
What is the name of the nerve that leaves the eye
Optic Nerve
What type of organ is the eye
A sensory organ
What is the role of the retina
It absoubes light energy and sends impulses to the brain via the optic nerve.
What is the Sclera, description and role
white coating of the eye that you can see. it protects the eye as it is tough
What is the Pupil
The whole in the eye which light enters
What is the Iris
Controls the diameter of the pupil (light levels into allowed the eye)
Name a hormone released into the bloodstream in humans in response to a dangerous situation.
Adrenaline
Effectors can be either muscles or what?
Glands
Where is adrenaline produced?
adrenal glands
In a reflex action, where do sensory and relay neurones meet?
Centeral Nervous Sytem
What organ in the body usually reacts to temperature first?
Skin
What is the name of the junction between two neurones?
synapse
What is the word for a change in the environment that a receptor cell responds to?
stimulus
What is the word for an organ or tissue that brings about the response in a reflex action?
Effector
Which system has longer lasting effects: the nervous system or hormonal system?
hormonal system
What system uses chemical messengers to coordinate and control the body?
endocrine system
Why are synapes important
To ensure that the impules can only travel in one direction
At a synapse, what is released by one neurone to cause an impulse in the other?
neurotransmitters or
chemical transmitter
Thyroxine is controlled by what type of feedback?
Negtive Feedback
Where are the adrenal glands located?
The adrenal glands lie on top of the kidneys.
Nerve cells can form many branches. How does this relate to their function?
to form networks with many other nerve cells.
Where is thyroxine produced?
Thiroid gland
Where is the thiroid gland located
the front of the neck
Where is ADH released
pituatry gland
What does ADH control
water levels
Why is ADH important
It alows us to keep our water conc in our blood at normal levels
Is water levels controlled by negitve or positive feedback
negitve feed back
what does ADH increase
ADH increases the permeability of the collecting duct of the kidney
what does inncreacing the permiablity of the kidneys cause
more water is reabsorbed
When is ADH realised
More ADH is released during dehydration
How does ADH effect the urine
more ADH = urine is more concerntrated
What does the cillary body do
Produces fluid in the eye
What is the name of the fuild in the eye
aqueous humor
What is the job of the suspensory ligaments
To tighten and pull the lens thinner
What causes colour blindess
A lack of or defect in the receptors which are sensitive to different colours of light
What tempurature is the human body kept at
37degrees
Why must the body be kept at a specific tempurature
To ensure enzymes are working at the optimum tempurature
Where is the Thermoregulatory Centre
In the hypothalamus
What does the Thermoregulatory Centre
Controlls interal tempuratures (like a thermostat
How does the body detect changes in interal tempuratures
Lots of tiny receptors that can detect tempurature changes
Where are most tempurature receptors in the body
- Skin
- Blood vessels
How does the Thermoregulatory Centre controll tempurature
The receptors send signals about the tempurature of the body to the Thermoregulatory Centre which decides if we are to hot or to cold. The Thermoregulatory Centre then sends signals around the body to either cool us down or heat us up.
What type of feed back does Thermoregulatory Centre use
Negitive feedback
- Body too hot = release cooling signals
- Body too cold = release warming signals
What are the two stratergies to warm up the body.
- Conserve heat
- Generate more
