Coordination and Response Flashcards Preview

Biology > Coordination and Response > Flashcards

Flashcards in Coordination and Response Deck (38)
Loading flashcards...

Describe the human nervous system

Made up of CNS (central nervous system - brain and spinal cord) and PNS (peripheral nervous system - cranial and spinal nerves)


Distinguish between voluntary and involuntary

- Voluntary actions: we choose to make and the decisions to make them occur in brains
- Involuntary: happens unconsciously without us having to think about them (blinking, breathing, beating of heart)


Sequence of event

stimulus -> receptor (detect the changes) -> coordinator (decides what to do) -> effector -> response


Describe a simple reflex arc

In a reflex arc, nerve impulses are transmitted to the spinal cord by the sensory neurone. Inside the grey matter of the spinal cord, the impulses are passed onto relay neurons. The impulses leave the spinal cord along motor neurons to go to effector.


Types of neurones

- Sensory: transmit impulses from sense organs to the brain and spinal cord
- Relay: that carry message from 1 part of the CNS to another
- Motor: neurons transmit impulses away from the brain and spinal cord to effector organs (muscles and glands)
- There’s a gap between 2 neurones called synapse where chemical transmitter substances are released to pass the impulse to the next neurone
- Myelin: an insulation helps speed up the impulses


Describe the action of antagonistic muscles to
include the biceps and triceps at the elbow joint

- Muscles are attached to bones by tendons
- Bones held together at a joint by ligaments
- When biceps contract, triceps relax and vice versa
- Antagonistic = to work against


Define sense organs

groups of receptor cells responding to specific stimuli: light, sound, touch, temperature and chemicals


Describe the structure and function of the eye,
including accommodation and pupil reflex

- Pupil reflex:
+ In dim light: circular muscles relax, radial muscles contract => pupil dilates
+ In bright light: circular muscles contract, radial muscles relax => pupil constricts
- Accomodation
+ Distant object: ciliary muscles relax, suspensory ligaments tighten => lens pulled into an elliptical shape
+ Near object: ciliary muscles contract, suspensory ligaments loosen => lens become spherical


Distinguish between rods and cones, in terms
of function and distribution

- Rod cells are distributed in the periphery of the retina. Responds to low intensity
- Cones are in the central of retina. Responds to high intensity. Fovea is made entirely of cones


Define a hormone

a chemical substance, produced by a gland, carried by the blood, which alters the activity of one or more specific target organs and is then destroyed by the liver


State the role of the hormone adrenaline

o Heart: increase in heart rate so that more oxygen and glucose are delivered to muscles for respiration
o Eye: pupil dilates so that more light reaches the retina
o Trachea: dilates so more airflow to lungs
o Brain + muscles: blood vessels dilate so that more blood flows to these organs
o Digestive system + other organs: blood vessels constrict so less blood flows here
o Liver: breaks down glycogen into glucose so that more glucose diffuses into blood for respiration


Compare nervous and hormonal control systems

- Nervous system:
+ Structure: nerves
+ Form of info: electrical impulses
+ Pathways: along neurones
+ Speed: fast
+ Duration of effect: short
+ Target area: small
+ Response: muscle contraction or secretion by glands
- Endocrine:
+ Structure: glands
+ Form of info: hormones
+ Pathways: in blood
+ Speed: slow
+ Duration of effect: long
+ Target area: whole tissue/organ
+ Response: many responses


Discuss the use of hormones in food

- Bovine somatotropin (BST) is a hormone used to increase milk production in cattle
- Concerns:
+ Animal welfare concerns as some cows treated with BST become infertile
+ Large quantites can be worrying


Define geotropism

a response in which a plant grows towards or away from gravity.
- Positively geotropic: grows in the same direction as gravity (roots)
- Negatively geotropic: grow in the opposite direction of gravity (shoots)


Define phototropism

a response in which a plant grows towards or
away from the direction from which light is coming
- Positively phototropic: shoot
- Negatively phototropic: roots



- Auxins are plant growth substances, produced by the shoot and root tips of growing plants.


Auxin in geotropism

- Auxins in the root builds up on the lower side → slow down the cell growth by inhibiting cell elongation → cells on upper side elongate more → root bends downward
- Auxins in the shoot builds up on the lower side → stimulates cell to elongate → grow more on lower side → bend upwards


Differences between sensory and motor neurones

- Cell body: Near end of neurone, just outside the spinal cord
- Dendrites: Present at end of neurone
- Axon: Very short
- Dendron: Very long
- Cell body: At start of neurone, indise the grey matter of the spinal cord
- Dendrites: Attached to cell body
- Axon: Very long
- Dendron: None


Auxins in phototropism

* If a shoot is exposed to light from one side
- More auxins are moving in the shaded side (from the tip of the shoot) -> stimulates cells to elongate
- Shoot bends toward the light.
- This is called positive phototropism.
* If a root is exposed to light in the absence of gravity
- More auxins are moving in the shaded side (from the tip of the root)
- Root bends away from the light because it is not sensitive to light
- This is called negative phototropism.


Define homeostasis

the maintenance of a constant internal environment


Define negative feedback

acts to ensure that the actual temp is as close to the pre-set temp as possible


What regulates the body temp and where can it be found

Hypothalamus found below the brain


Controlling temp: in the heat

- Arterioles undergo vasodilation - increases blood flow through capillaries so more heat can be lost through radiation and convection
- Sweat glands produce sweat => sweat on skin evaporates to cool the body
- Hair lies flat => less air is trapped => heat lost through convection


Controlling temp: in the cold

- Arterioles undergo vasoconstriction
- Sweat glands stop producing sweat
- Hair stands up to trap air to reduce heat loss
- Shivering by the muscles so releasing heat from respiration=> blood flows through muscles and is warmed


Describe the control of the glucose content
of the blood by the liver, and by insulin and
glucagon from the pancreas

- High glucose concentration
+ Pancreas detected, secretes insulin => converts glucose into glycogen and store it in the liver
- Low glucose concentration
+ Pancreas detected, secretes glucagon => converts glycogen into glucose and diffuses into blood


Define drug

any substance taken into the body that modifies or affects chemical reactions in the body


Synthetic plant hormones

- Synthetic auxins are very effective as selective weedkillers
- Auxins increase growth rate of affected weeds, increasing the rate of cell division. Weeds cannot provide enough food from photosynthesis to maintain this rate of growth and soon die
- More likely to be absorbed by broad-leaved (dicots) weeds => leaving grasses (moncotyledons) unharmed


Describe the medicinal use of antibiotics for the
treatment of bacterial infection

Antibiotics destroy pathogens by disrupting cell wall formation, inhibiting protein synthesis, and metabolism in the cell


Explain why antibiotics kill bacteria but not viruses

Viruses do not have cell walls and they live inside host cells, taking over their metabolic process


Describe the effects of the abuse of heroin

- A powerful depressant that slows down the impulses along neurones transferring information from pain receptors to the brain => experiences euphoria
- Feeling of pain is unbearable and addicts have to take heroin to reduce pain => develops tolerance and dependence => addiction