Coordination, Response & Homeostasis Flashcards

Flashcards covering the mammalian nervous system, reflexes, synapses, sense organs, hormones, homeostasis, and tropisms in plants.

What makes up the central nervous system (CNS)?

The brain and spinal cord.

What makes up the peripheral nervous system (PNS)?

All of the nerves in the body.

What are the two main roles of the mammalian nervous system?

To make sense of our surroundings and respond to them, and to coordinate and regulate body functions.

What are nerve impulses?

Electrical signals that pass along nerve cells known as neurones.

What is a nerve?

A bundle of neurones.

What are the three main types of neurones?

Sensory, relay, and motor.

What is the function of sensory neurones?

Carry impulses from sense organs to the CNS (brain or spinal cord).

What is the function of relay neurones?

Found inside the CNS and connect sensory and motor neurones.

What is the function of motor neurones?

Carry impulses from the CNS to e ectors (muscles or glands).

Describe the reflex arc when touching a pin.

The pin (the stimulus) is detected by a pain/pressure/touch receptor in the skin, Sensory neurone sends electrical impulses to the spinal cord (the coordinator), Electrical impulse is passed on to relay neurone in the spinal cord, Relay neurone connects to motor neurone and passes the impulse on, Motor neurone carries impulse to a muscle in the leg (the e ector), The muscle will contract and pullthe foot up and away from the sharp object(the response)

What are 3 characteristics of reflex actions?

Automatic, Fast, Protective

What is a synapse?

A junction between two neurones.

What are neurotransmitters?

Chemical messengers released from the presynaptic neurone that diffuse across the synaptic gap and bind with receptor molecules on the postsynaptic membrane.

What do receptors do?

They detect a change in the environment and stimulate electrical impulses in response

What are the main structures of the eye?

Cornea, iris, lens, retina, and optic nerve.

What is the function of the Iris of the eye?

Muscle that controls how much light enters the pupil.

What is the function of the Optic nerve?

Sensory neurone that carries electrical impulses from the eye to the brain.

What is the function of the Retina?

Layer of light receptor cells that detect light intensity and color.

What changes during the process of eye accommodation?

Contraction or relaxation of the ciliary muscles and adjustment of tension in the suspensory ligaments

What is the difference between Rod and Cone cells of the eye?

Rod cells can detectlight atlow levels, three di erenttypes of cones can detectlight at three di erent wavelengths, enabling colour vision

What is a hormone?

A chemical substance produced by a gland and carried by the blood, which alters the activity of one or more specific target organs.

Explain the functions of Insulin and Glucagon

Insulin is produced when blood glucose rises and stimulates liver and muscle cells to convert excess glucose into glycogen to be stored, Glucagon is produced when blood glucose falls and stimulates liver and muscle cells to convert stored glycogen into glucose to be released into the blood

What is the overall effect of the hormone Adrenaline?

It causes a range of di erentthings to happen in the body, all designed to prepare itfor movement(ie ght or ight).

What is homeostasis?

The maintenance of a constant internal environment.

What are some internal conditions regulated by homeostasis?

Temperature, blood pressure, water concentration, and glucose concentration.

How does negative feedback work?

If a level of something rises, control systems are switched on to reduce it again, if the level of something falls, control systems are switched on to raise it again.

What is Type 1 Diabetes?

A condition where the blood glucose levels are not able to be regulated as the insulin-secreting cells in the pancreas are not able to produce insulin

Give two examples of Stimulus and their related Tropism plant responses

Gravity - Gravitropism, Light - Phototropism

What is a positive tropism?

Growth towards a stimulus.

What is a negative tropism?

Growth away from a stimulus.

What is auxin?

A growth hormone that controls the direction of growth of roots or stems.

What are the effects of Auxin on shoots and roots?

Auxin increases the rate of growth in shoots, causing the shootto grow upwards, higher concentrations of auxin results in a lowerrate of cell elongation