Ch 14 - (Coordination & Response) Flashcards
What are the 2 components that the nervous system is made up of?
- Central nervous system (CNS)
- Peripheral nervous system (PNS)
Which organ does CNS involve?
Brain and spinal cord.
Which organ does PNS involve?
sensory and motor neurons.
What are electrical impulses?
electrical signals that pass along nerve cells (neuron)
What are glands and muscles called?
Effectors because they act when they receive nerve impulses or hormones.
Define sensory impulse.
Nerve impulses from the sense organ to the Central nervous system are called sensory impulses.
What is a nerve?
A bundle of neurons
What is a neuron?
Individual specialized cells that make up the nervous system
What are the 3 types of neurons?
- Motor neurons (effector neurons)
- Sensory neurons
- Relay neurons (connector or multipolar neurons)
what do motor neurons do?
carry impulses from CNS to effectors (muscles and glands).
what do sensory neurons do?
carry impulses from sense organs to CNS
What do relay neurons do?
they make connections to the sensory and motor neurons inside the CNS
Define synapses.
Junctions where neurons connect with each other
What parts does a neuron consist of?
- Cell body
- Dendrites
- Nerve fibre
Give a description of cell body as a part of a neuron.
Consists of a nucleus surrounded by cytoplasm
Give a description of dendrites as a part of a neuron.
Fibers, which branch from the cell body to make contact with other neurones.
Give a description of a nerve fibre as a part of a neuron.
a long filament of cytoplasm surrounded by an insulating sheath runs from the cell body of a neurone.
why do nerves contain a mixture of sensory and motor fibres?
So it can carry many different impulses.
Which direction do sensory and motor nerves travel in?
Sensory travel in one direction and motor travel in the opposite direction.
What is the structure of sensory neuron?
- Long
- has a cell body in the center of the axon
What is the structure of relay neuron?
- Short
- very small with a short axon
What is the structure of motor neuron?
- long
- has a large cell body at the top of the cell. This is where impulses start
what is the axon insulated by?
- Fatty sheath with a small with an uninsulated section called (nodes)
- Electrics, impulses jump from one node to another
Describe the process about what happens when an electrical impulse arrives at synapses.
- Impulse arrives at the end of Presynaptic neuron.
- Vesicles move towards, and fuse with Presynaptic membrane. This releases neurotransmitters into the synaptic cleft
- The neurotransmitters diffuse across the synaptic cleft down q concentration gradient
- Neurotransmitters attach to receptors on the postsynaptic membrane
- Triggers an impulse which travels along the postsynaptic neuron
- Transmitters are recycled or destroyed when an impulse is sent.
Why are neuro transmitters destroyed?
To prevent continued stimulation
What is the specialty of synapses?
only place where drugs can act of affect the nervous system
Define reflex action.
A means of automatically and rapidly integrating and coordinating stimuli with the responses of effectors (muscles and glands)
What is a voluntary response?
Make a conscious decision so it starts with the brain
what is an involuntary response?
does not involve brain as the coordinator
What are some pointers about reflex responses?
- does not involve the brain
- automatic and rapid response
- quicker
- minimizes damage of the body
Describe how an impulse is sent when a pin is detected by the foot.
- The pin (stimulus) is detected by a pain/pressure/touch receptor is the skills.
- Sensory neurons send electrical impulses to the spinal cord (coordinator)
- Electrical impulses is passed onto relay neuron in spinal cord
- Relay neurons connect to motor neurons and pass the impulse on
- Motor neurone carries impulses to a muscle in the leg
- Muscle contracts and pulls fit up from sharp object
What is the reflex pathway?
- Stimulus (tapping the tendon below the kneecap)
- Receptor (stretch receptor)
- Sensory neuron
- Relay neuron: Coordinator (spinal cord)
- Motor neuron
- Effector
- Response
Define sense organs.
A group of receptor cells responding to specific stimuli such as light, sound, touch, temperature and chemicals.
What do receptor cells do?
Detect a change in the environment and stimulate electrical impulses in response.
What is skin sensitive to?
- Pressure
- Temperature (Hot, cold)
- pain
Sense: Touch and temperature
What is tongue sensitive to?
- chemicals in foods and drinks
Sense: Taste
What is nose sensitive to?
- chemicals in the air
Sense: Smell
What is ear sensitive to?
- sound and movement
Sense: Hearing & balance
What is eye sensitive to?
- light
Sense: Sight
Describe the process of when the receptor cell in the sense organ has been stimulated.
- It generates an electrical impulse
- Passed on to sensory neuron which carries impulse to CNS
- Response is decided and impulse is passed on to motor neurone (via a relay neurone)
- Motor neuron carries impulse ro effector
- Effector carries out the response.
Define eye.
Sense organ containing receptor cells that are sensitive to light (rod cells) and color (cone cells)
What is the function of cornea?
Transparent lens that refracts (bends) light as it enters the eye.
- refracts light and helps to focus it
What is the function of iris?
- colored ring of circular and radial muscles
- controls how much light enters the pupils.
What is the function of the lens?
- Transparent disc that can change shape to focus light onto the retina.
- refracts light to focus it onto the retina
What is the function of retina?
contains light receptor cells - rods (detect light intensity) and cones (detector colours)
- detects different colours
What is the function of optic nerves?
sensory neuron that carries impulses from retina to the brain
What is the function of pupil?
hole that allows light to enter the eye
Which part is the blind spot?
Point where optic nerve joins the retina, there are no light sensitive rods and cone cells on the part of retina
What happens when light falls on the blind spot?
- not result in image being detected
- brain ‘fills in from surrounding light so we don’t see a black hole where no light has fallen.
what is the pupil reflex?
Reflex action carried out to protect the retina from damage in bright light and protects us from not seeing objects in dim light.
What happens to the pupil in dim light?
pupil dilates (widens) in order to allow as much light into the eye as possible to improve bision
What happens to the pupil in bright light?
pupil constricts (narrows) in order to prevent too much light entering the eye damaging the retina
What is pupil reflex an example of?
Antagonistic muscle groups
What muscles work antagonistically?
Radial muscles and the circular muscles
What happens to the antagonistic muscles in dim light?
- Photoreceptors detect change in environment (dark)
- radial muscles contract
- circular muscles relax
- pupil dilates (diameter of pupil widens)
- more light enters the eyes.
What happens to the antagonistic muscles in bright light?
- Photoreceptors detect change in environment (bright)
- radial muscles relax
- circular muscles contract
- pupil constricts (diameter of pupil narrows)
- less light enters the eyes
What is accommodation?
The way lens bring about fine focusing is called accommodation.
How do eyes accommodate to focus on near and distant objects?
- lens is elastic and it’s shape is changed when the suspensory ligaments attached become tight of lose.
- changes are brought by contraction and relation of the ciliary muscles.
What happens when an object is close up?
- ciliary muscle contracts (ring of muscle decreases in diameter)
- causes suspensory ligaments to loosen up
- stops suspensory ligaments from pulling on the lens, which allows the lens to become fatter
- more light is refracted
What happens when an object is far away?
- ciliary muscles relax (the ring of muscles increases in diameter)
- causes the suspensory ligaments to tighten
- suspensory ligaments pull on the lens, causing it to become thinner
- less light is refracted
What are the 2 types of receptor cells?
- Rods - sensitive to dim light
- Cones - distinguish between different colours in bright light
How many types of cone cells are there?
3 types:
- Red
- Blue
- Green
What is fovea?
area of retina where almost all of cone cells are found.
What is a hormone?
A chemical substance produced by a gland and carried by the blood.
What do hormones do?
- alter the activity of one or more specific target organs
- chemicals which transmit information from one part of an organism to another
What is endocrine system?
The glands that produce hormones in animals are known collectively as the endocrine system.
What are the major endocrine glands in the body?
- Pituitary gland
- Thyroid gland
- Pancreas
- Adrenal glands
- Testes
- Ovaries
What does pituitary gland do?
The ‘master gland’ situated at the base of the brain
What does thyroid gland do?
produces thyroxine
What does pancreas do?
- produces insulin
- produces hormones to regulate blood glucose levels
- produces digestive enzymes such as lipase and amylase
What does adrenal glands do?
produces adrenaline
What do testes do?
produces testosterone
what do ovaries do?
produces estrogen
How are endocrine glands transported around the body?
- good blood supply which gets into bloodstream (plasma) so they target organs to bring response
- hormones affect cells which target receptors that bind to. Found on cell membrane, or inside cells. Receptors have to be complementary.
- liver regulates hormones in blood, transforming or breaking down any that are in excess.
What is the role of adrenaline?
Readies the body for a ‘fight or flight’ response
What is the role of insulin?
lowers blood glucose levels
What is the role of testosterone?
main sex hormones in male cells
What is the role of oestrogen?
main sex hormones in female cells
What is the effect of adrenaline?
increases heart and breathing rate, dilates pupils.
What is the effect of insulin?
Causes excess glucose in the blood to be taken up by the muscles and liver and converted into glycogen for storage
What is the effect of testosterone?
development of secondary sexual characteristics in males
What is the effect of oestrogen?
development of secondary sexual characteristics in females and controls menstrual cycles.
Include the following about the nervous system:
- Made up of
- Type of message
- Speed of transmission
- Length of effect
- Made up of - nerves (neurons), brain, spinal cord
- Type of message - electrical impulse
- Speed of transmission - very fast
- Length of effect - short until nerve impulses stop
Include the following about the endocrine system:
- Made up of
- Type of message
- Speed of transmission
- Length of effect
- Made up of - glands
- Type of message - chemical hormone
- Speed of transmission - slower
- Length of effect - longer until hormone is broken down.
How is blood glucose levels controlled?
A negative feedback mechanism involving the production of two hormones (insulin and glucagon)
Where is insulin and glucagon produced?
Pancreas
When is insulin produced?
when blood glucose rises and stimulates liver and muscle cells to convert excess glucose into glycogen to be stored.
when is glucagon produced?
when blood glucose falls and stimulates liver and muscle cells to convert stored glycogen into glucose to be released into blood
What is the difference between glucagon and glycogen?
- glucagon is a hormone
- glycogen is a polysaccharide glucose is stored as
What is the difference between fight and flight in adrenaline?
Flight = remove one self rapidly from a dangerous situation
Fight = if flight is not possible, resort to physical combat to overcome danger
What happens when adrenaline is released into the body?
- Increasing blood glucose concentration for increased respiration in muscle cells
- Increases pulse rate so O2 can be delivered to msycke cells and CO2 can be removed quickly
- Diverting blood flow toward the muscle cells
- Dilating pupils so more information can be sent to the brain.
What are the additional effects of adrenaline?
- increasing concentration of glucose in the blood - helps deliver more important glucose to muscles for respiration
- Increasing heart rate - to ensure that all muscles are well prepared for High level of activity in a fight or flight situation.
Define homeostasis.
The maintenance of a constant internal environment.
What dies Homeostasis help the body with?
- Maintains internal conditions within the body (Temp, blood pressure, water conc., glucose concentration)
- need to be kept in within set limits
- if condition deviates, body will not function properly
When is insulin secreted?
Blood glucose levels are high directly after a meal
what happens to kidneys with insulin and level of glucose?
- Level is too high, glucose is excreted and lost in urine
What does the body do to prevent insulin from getting excreted when level of glucose is high?
- Insulin temporarily converts excess glucose into glycogen in the liver and the muscle cells
- Insulin decreases blood glucose concentration
- Glycogen is concerted back to glucose several hours later when blood glucose kevel has dipped due to respiration.
When does negative feedback occur?
Change from the ideal or set point and return conditions to this set point and return conditions
How does negative feedback work?
-If level of smth rises, control systems are switched on to reduce it again
- if level of smth falls, control systems are switched on to raise it again.
What is type 1 diabetes?
A condition where the blood glucose levels are not being able to be regulated as the insulins secreting cells in the pancreas are not able to produce insulin.
What happens in type 1 diabetes and how is it treated?
- blood glucose levels are far too high
- Extra insulin converts glucose into glycogen, reducing the blood glucose level
- Treated by injecting insulin
What are the symptoms of type 1 diabetes?
- extreme thirst
- wariness or tiredness
- blurred vision
- weight loss
- loss of consciousness
What do type 1 daubers’ patients have to keep a check of?
- monitor their blood glucose levels
- physical activity and diet affect the levels of glucose
what is the control of body temperature called?
Homeostatic mechanism
How does temperature regulation of the skin work?
- Controlled by brain which contains receptors sensitive to the temperature of the blood.
- temp receptors on the skin sends nervous impulse to the brain via sensory neurons
- brain responds by sending effectors in the skin to maintain the temoerature within the narrow range optimum of 37°C
what provides insulation on the skin to prevent too much heat from being lost?
Fatty tissues under the dermis
what is the response when we are hot?
- Sweat secreted by sweat glands
- cools skin by evaporation
- heat energy from body is lost
- hair lies flat against the skin that allows air to circulate freely
- increases heat transfer to environment by radiation
What is the response when we are cold?
- skeletal muscles contract when we shiver
- involuntary muscle contractions need energy from respiration, some is released as heat.
- erect hairs trap a layer of air around the skin as insulator
What is vasoconstriction?
- When se are cold, blood flowing in capillaries slows down because arterioles leading to skin capillaries get narrower
- Reduces the amount of heat lost from blood by radiation.
What is vasodilation?
When we are hot, blood flows in capillaries because blood vessels to the skin get wider
- more heat is lost
- cools down body
How is tropisms in plants?
- respond for survival (light, water, gravity)
- much slower
- grows towards and away from stimuli
Define gravitropism or geotropism.
Growth towards or away from gravity.
what is the positive response for geotropism?
growth towards gravity (eg roots)
what is the negative response for geotropism?
growth away from gravity (eg shoots)
Define phototropism.
growth towards or away from the direction of the light
what is the positive response for phototropism?
growth towards light (eg shoots)
what is the negative response for phototropism?
Growth away from light (eg roots)
How the phototrophic and gravitropic response of shoots?
How the phototrophic and gravitropic response of roots?
