B5 - Homeostasis and response Flashcards
4.5.1
1)What is maintaining controlled conditions within the body under?
2)What do the automatic control system involve?
3)What do all control systems include?
1)Under involuntary(automatic) control.This means that the brain stem or a non conscious part of the brain and the spinal cord are involved in maintaining homeostasis
2)Nervous system or chemical response
3)Cells called receptors-which detect stimuli(changes the environment
Coordination centres(brain, pancreas,spinal cord)
receive information and process information from receptors
Effectors(muscle or glands) which bring about responses which restore optimum levels
1)What is Homeostasis?
2)What does homeostasis maintain optimal conditions for?
3)In the human body,what do these optimal conditions control?
1)Homeostasis is the regulation of internal conditions of a cell or organism to maintain optimum function in response to internal and external changes
2)Homeostais maintains optimal conditions for enzyme action and cell functions
3)In the human body these include control of:blood glucose concentration, body temp, and water levels
4.5.2.1
1)What does the human nervous system consist of?
2)What does the nervous system enable humans to do?
3)How is information sent through the nervous system?
4)What is a bundle of neurones known as?
1)Central nervous system(CNS)-the brain and spinal cord, peripheral nervous system(PNS)-all nerves in the body
2)The nervous system enables humans to react to their surroundings and coordinate their behaviour
3)Information is sent through the nervous system as electrical impulses-electrical signals that pass along nerves cells known as neurones
4)A bundle of neurones is known as a nerve
What are adaptions of the nervous system?
-Neurones have a cell body(Where the nucleus and main organelles are found) and cytoplasmic extensions from this body called axons and dendrites
-Some human neurones have axons over a meter in length(1-4 micrometers wide)
-This is far more efficient than having multiple neurones to convey information from the CNS to effectors-less time is wasted transferring electrical impulses from one cell to another
-The axon is insulated by a fatty myelin sheath with small uninsulated sections along it(nodes)
1)How does information pass?
2)What is the CNS?
3)What does the CNS do?
4)Recall the pathway through the nervous system
1)Information from receptors passes along cells(neurones) as electrical impulses to CNS
2)CNS is the brain and the spinal cord
3)The CNS coordinates the response of effectors which may be muscles contracting or glands secreting hormones
4)Stimulus-receptor-coordinator-effector-response
1)Must you be conscious for a reflex?
2)When does awareness of response happen?
1)An involunatary(or reflex) response does not involve the conscious part of the brain as the coordinator of the reaction
2)Awareness of response after response has been carried out
4.5.2.2
1)What system is the brain apart of?
2)Describe the brain
1)The brain is apart of our central nervous system
2The brain is made of billions of interconnected neurones and is responsible for controlling complex behaviours.Within the brain are different regions that carry out different functions.
1)3 different regions of the brain
2)Describe their functions
1)The cerebral cortex, the cerebellum, the medulla
2)
-The cerebral cortex:this is the outer layer of the brain which is divided into two hemispheres. It’s highly folded and is responsible for higher-order processes such as intelligence, memory, consciousness and personality
-The cerebellum:this is underneath the cerebral cortex and is responsible for balance, muscle coordination and movement
-The medulla:this region controls unconscious activities such as heart rate and breathing
1)Why is the brain extremely difficult for neuroscientists to study to find out how it works?
2)Why is our understanding of the brain limited?
3)What does limited understanding of the brain mean?
1)The brain is incredibly complex and a delicate organ
2)Because the brain is so complex and different regions can not be studied in isolation
3) treating brain damage and disease is very difficult; in addition, any potential treatment carries risks of further damage occurring which can lead to increased problems l
Accidental damage could lead to speech or motor issues, or changes to personality which are permanent
Neuroscientists have been able to map the regions of the brain to particular functions by studying patients with brain damage, electrically stimulating different parts of the brain and using MRI scanning techniques.
What are these techniques?
-Patients with brain damage can be studied to see what effect it has on them physically or on their personality or capabilities
(The most famous example of this is Phineas Gage, a railroad construction worker who survived a large iron rod being driven completely through his head – his frontal left lobe was completely destroyed and his personality and temperament changed drastically)
-Tiny electrodes can be pushed into different parts of the brain, tiny jolts of electricity stimulate these regions and the effects can be observed
(For example, if a region in the medulla responsible for movement is stimulated, the movement caused can be observed)
-MRI scanners are very important diagnostic tools used to study the brain and other regions of the body using magnetic fields and the effect these have on protons in the water molecules of the body
-Functional MRIs can produce images of different regions of the brain that are active during different activities like listening to music or recalling a memory (the scanners can detect changes in blood flow – more active regions of the brain have increased blood flow)
1)What are the benefits of procedures carried out on the brain and the nervous system?
2)What are the risks of the producers carried out on the brain and the nervous system?
1)The benefits of procedures being carried out usually involve improving the quality of someone’s life (as the procedure is used to treat a disorder of some kind)
2) risks of more permanent damage, some of these will be because we still don’t fully understand how the brain and nervous system works
4.5.2.3
1)what type of organ is the eye?
2)What are receptors?
3)What type of receptor cells does the eye contain?
1)The eye is a sense organ containing receptors sensitive to light intensity and colour
2)Receptors are groups of specialised cells that can generate an electrical impulse in a sensory neurone
3)The eye contains two types of receptor cell: rod cells which are sensitive to light intensity and cone cells which are sensitive to different wavelengths of visible light (colour)
1)What is the purpose of the eye?
2)What is the retina?
3)Description of the eye
1)The purpose the eye is to receive light and focus it onto the retina at the back of the eye
2)The retina is where the rod and cone cells are located
3)The eye is an organ made from several different types of tissue. All of the structures function together to allow light to hit the retina, which sends signals to the brain
Eye structure and describe its functions
-Cornea
-Iris
-Lens
-Retina
-Optic nerve
-Pupil
-Cornea:Transparent lens that refracts(bends) 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:controls 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
1)What is the pupil reflex?
2)How is the pupil reflex controlled?
3)What happens to the pupil in dim light?
4)What happens to the pupil in bright light?
1)This is a reflex action carried out to protect the retina from damage in bright light and protect us from not seeing objects in dim light.It’s a reflex action so it happens automatically.
2)The reflex action is controlled by two groups of muscle.The radial muscle and the circular muscles
3)In dim light, the pupil dilates (widens) in order to allow as much light into the eye as possible
4)In bright light, the pupil constricts (narrows) in order to prevent too much light entering the eye and damaging the retina.Very bright light can damage the receptor cells of the retina, the pupil reflex protects the eye by altering the diameter of the pupil.
