topic 11 - coordination and response Flashcards
what is the excretory product of the lungs
CO2 and water
excretory product of kidneys
urea
excretory product of skin
sweat
why do animals need to respond to changes in the environment?
to coordinate the activities of internal organs
how do animals maintain their internal environment?
through a process called homeostasis
5 examples of what homeostasis controls
- water content (of an individual cell or of the body fluids of an organism)
- temperature
- pH
- blood pressure
- blood glucose concentration
2 communication systems in mammals
- the nervous system
- the endocrine system
what is homeostasis?
the control or regulation of the internal conditions of a cell or organism
what is required for a co-ordinated response?
- stimulus - change in environment (heat)
- receptor - what detects stimuli (hand)
- coordination centre - brain, spinal cord
- effector - muscle or gland that brings response (muscle contracts)
- response - body’s reaction (withdraw hand)
why do plants grow in response to light?
- plants need to be able to grow in response to light, to ensure their leaves can absorb light for photosynthesis
- they also need to be able to grow in response to gravity, to ensure that shoots grow upwards and roots grow downwards
what is a tropism?
The directional growth responses made by plants in response to light and gravity
what is a positive tropism?
when the growth is towards the stimulus
what is a negative tropism?
when the growth is away from the stimulus.
what is a response to light called?
phototropsim
what is a response to gravity called?
geotropism
what is geotropism and what are the positive and negative responses?
- growth towards or away from a gravitational pull
- a positive geotropic response is growth towards gravity e.g. the roots
- a negative geotropic response is growth away from gravity e.g. the shoot
what is phototropism and what are the positive and negative responses?
- growth towards or away from a light source
- a positve phototropic response is growth towards light e.g. shoots
- a negative phototropic response is growth away from the light e.g. roots
what are auxins?
plant growth regulators (similar to hormones in animals) produced by plants to coordinate and control directional growth responses such as phototropism’s and geotropism’s
where are auxins produced?
the tip of the shoots and the roots
how is the distribution of auxins affected?
- in the shoots is affected by light and gravity
- in the roots is primarily affected by gravity alone
what are auxins like in the shoots?
- the lower side grows faster than upper side (more auxin = more cell elongation), so the shoot grows upwards
- they stimulate the cells in this region to elongate; the more auxin there is, the faster they will elongate and grow
what are auxins like in the roots?
In the roots, the lower side grows slower than the upper side (as auxin inhibits cell elongation and growth in roots), so the root grows downwards
what happens when the sun shines directly on the tip of a plant?
- auxin is distributed evenly throughout and the cells in the shoot grow at the same rate - this is what normally happens with plants growing outsidew
what happens when the sun is shining predominantly on one side of the plant?
the auxin produced in the tip concentrates on the shaded side, making the cells on that side elongate and grow faster than the cells on the sunny side
4 facts about the nervous system
- information is sent through the nervous system as electrical impulses – these are electrical signals that pass along nerve cells known as neurones
- these impulses travel along neurones at very high speeds, allowing rapid responses to stimuli
- the nervous system coordinates the activities of sensory receptors, decision-making centres in the CNS, and effectors such as muscles and glands
- the nervous system is used to control functions that need instant (or very rapid) responses
6 facts about the endocrine system
- information is sent through the endocrine system as hormones
- hormones are carried by the blood and can therefore circulate around the whole body
- hormones transmit information from one part of the organism to another and bring about a change (they provide a signal that triggers a response)
- they alter the activity of one or more specific target organs
- hormones are used to control functions that do not need instant responses
- hormones are produced by endocrine glands.
3 differences between the endocrine and nervous systems
- nervous system has electrical impulses, endocrine has chemical hormones
- nervous impulses travel extremely fast, endocrine are slower
- nervous impulses last for a short period of time while endocrine last longer
what does the nervous system consist of?
- the central nervous system (CNS) - brain and spinal cord
- the peripheral nervous system (PNS) - all the nerves in the body
how is info sent out in the nervous system?
electrical impulses through neurones. a bundle of neurones is a nerve
how does the nervous system work?
the PNS is spread to all parts of the body, including sense organs. the CNS therefore acts as a central coordinating centre for all impulses coming in or out.
three types of neurones
- sensory
- relay
- motor
what does the sensory neurone do?
carry signals from the receptor to the CNS
what does the relay neurone do?
carry signals from the CNS to CNS
what does the motor neurone do?
carry signals from the CNS to the effector
what is the gap between two neurones called?
synapse
what are neurotransmitters?
the chemical signalling molecules used to transfer the signal between neurones at a synapse
be able to draw a synapse
- synapse
- vesicles containing neurotransmitters - move by diffusion
- presynaptic membrane
- postsynaptic membrane
- neurotransmitter receptors
factors of the reflex arc and be able to draw it
- stimulus
- receptor
- sensory neurone
- relay neurone
- motor neurone
- effector
- response
receptor of the eye
retina
9 features of the eye
- ciliary muscles
- lens
- retina
- optic nerve
- sclera
- iris
- conjuctiva
- cornea
- pupil
function of cornea
transparent lens that refracts light as it enters the eye
function of iris
controls how much light enters the pupil
function of lens
transparent disk that can changes shape to focus light on retina
function of retina
contains light receptor cells
function of optic nerve
sensory neurone that carries impulses between the eye and brain
function of pupil
hole that allows light to enter the eye
function of conjunctiva
clear membrane that covers the white of the eye and the inside of the eyelids; it lubricates the eye and provides protection from external irritants
function of ciliary muscle
a ring of muscle that contracts and relaxes to change the shape of the lens
function of suspensory ligaments
ligaments that connect the ciliary muscle to the lens
function of sclera
the strong outer wall of the eyeball that helps to keep the eye in shape and provides a place of attachment for the muscles that move the eye
what happens to the eye when an object is close up
- the ciliary muscles contract
- the suspensory ligaments to loosen
- the lens to becomes fatter
- light is refracted more
what happens to the eye when an object is far away
- the ciliary muscles relax
- this causes the suspensory ligaments to tighten
- the suspensory ligaments pull on the lens, causing it to become thinner
- light is refracted less
what happens to the eye when in dim light
the pupil dilates in order to allow as much light into the eye as possible to improve vision
what happens to the eye in bright light
the pupil constricts in order to prevent too much light from entering the eye and damaging the retina
what is vasodialation?
blood vessels in your body widening, allowing more blood to flow through them and lowering your blood pressure
what is vasoconstriction?
the constriction of blood vessels, which increases blood pressure
why do we sweat?
sweating cools the skin by evaporation which uses heat energy from the body to convert liquid water into water vapour
5 main hormones
- adrenaline
- insulin
- testosterone
- progesterone
- estrogen
source, role and effect of adrenaline
- adrenal gland
- readies the body for a ‘fight or flight’ response
- increases heart and breathing rate
source, role and effect of insulin
- pancreas
- lowers blood glucose levels
- causes excess glucose in the blood to be taken up by muscles and liver and converted to glycogen for storage
source, role and effect of testosterone
- testes
- main sex hormone in males
- development of secondary sexual characteristics in males (hair growth, height growth)
source, role and effect of progesterone
- ovaries
- maintains uterus lining for pregnancy
- maintains uterus lining to cushion fertilised egg, allowing it to develop
source, role and effect of estrogen
- ovaries
- main female sex hormone
- development of secondary sexual characteristics in females (menstruation, breast development)
