human nervous system (b7, 7.2, 7.3, 7.4)

give examples of situations in which adrenaline secretion increases

"fight, flight" reponses

Compare nervous and hormonal control systems

(speed of action, nature of message, duration of response, area of response, examples of processes controlled) Hormonal: - usually slow, transmitted chemically through blood, affects any organ, effects short term and long lasting, can affect growth, can bring about specific chemical changes and regulates metabolism Nervous: - immediate/ rapid transmitted electro chemically through nerve fibres and chemically across synapses, affects only particular muscles or glands,

Describe the different types of homeostasis

- osmoregulation -glucosregulation -thermoregulation

How are blood glucose levels regulated?

Blood glucose levels are regulated and monitored by the pancreas. - insulin released when blood levels aee too high. Liver stores excess glycogen - Glucagon released when blood glucose levels are low. Livers converts glycogen into glucose and relases it into blood. (?)

Describe the human nervous system

Central and peripheral nervous system central nervous system (brain and spinal cord= areas of coordination) peripheral nervous system (serve to coordinate and regulate body functions) contains nerves, and everything other than brain and spinal cord

how does the body maintain a constant body temperature in humans? (sweating, shivering, vasodilation, vasoconstriction)

Too Hot: - hairs lie flat (less air trapped so less insulation to trap heat) - Sweat produced (evaporates and takes heat away) - blood vessels near surface widen (lets more blood through so more heat is lost through radiation) too cold: - muscles shiver to generate heat - sweat glands stop producing heat - hairs on body stand on end--> traps heat to insulate body - Blood vessels at surface close up (vasoconstriction) --> cuts down flow of blood to surface and less heat loss through radiation.

Define hormone

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

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

accommodation is the ability of the lens system to produce sharp images of objects at different distances. - Distant: ciliary muscles relax and suspensory ligaments pull tight making lens pull thin --> light doesn't bend much - Close: ciliary muscles contract, allowing lens to go fat--> bends light more pupil or iris reflex is automatic reflex action of eye in controlling size of pupil, and thereby controlling the amount of light that falls on retina. - low: radial muscles contracted, circular muscles relaxed (pupils get wider to let in more light) - bright: ciliary muscles contract, radial muscles release. (pupils narrows to protect retina from bleaching) structure of eye: sclera, retina, pupil, ciliary muscles, suspensory ligaments, optic nerve, cornea, lens, iris, choroid, aqueous humour, virtuous humour

What is a nerve?

bundle of many nerve fibres enclosed within a protective sheath. Nerve fibres are the long axons of neurones together with any associated tissues.

What is glucose and how is it important?

glucosregulation glucose= type of sugar used by body to produce energy. (eating causes glucose levels to rise, and similarly exercising causes it to fall)

State role of hormone adrenaline in chemical control of metabolic activity

increases blood glucose concentration and pulse rate

What is homeostasis?

maintenance of constant internal environment

What are auxins?

plant growth hormones made in tips of stems and roots. Why does plants bend toward the light? Sunlight breaks down auxins. therefore side that dont get a lot of sunlight grow more and auxins build up.

What is osmoregulation and why is it important?

regulation of body content in of water. Amount of water in urine adjusted by kidneys.....

define phototropism

response in which plant grows towards or away from direction from which light is coming

define geotropism

response in which plant grows towards or away from gravity

Describe simple reflex arc

simple reflex arc= nerve pathway involved in reflex action (reflex action= rapid automatic response to a stimulus) 1. stimulus (change) picked up by body 2. receptor/sensor (part of body that detects change) 3. sensory neuron (carries signal from sensory to cns 4. cns (made up of brain and spinal cord 5. motor neuron (carries signal from cns to effector) 6. effector (part of body that responds)

What are nuerons?

specialized cells that conduct electrical impulses through the body.