book

• which system in the human body is responsible for transporting substances around the body?


  circulatory system
• what happens when the body gets too hot?

  • sweating- sweat is secreted by sweat glands. this sweat evaporates due to the excess heat from the blood flowing near the skin from blood vessels. this causes the body to cool down.
  • vasodilation- (the blood vessels carrying blood near the skin increase in diameter which causes more heat to be carried near the skin where it can be lost to the air.
  • hairs on our skin lay flat- reduces their insulation abilities
• what happens when the body gets too cold

  • sweating is reduced
  • vasoconstriction- the narrowing of blood vessels at skin surface to reduce heat loss through the skins surface
  • hairs on our skin stand on end- increases their insulating abilities by trapping a layer of air between our skin and external environment.
• why is maintaining optimum temperature important?


  the optimum temperature is 37 degrees. it needs to stay at this temperature for the enzymes in the body to function properly.
• what is homeostasis?


  the bodys maintenance of internal conditions for optimum enzyme and cell activity.
• what are some examples of what the body needs to regulate


  water levels, temperature and sugar levels.
• what is an enzyme


  biological catalysts
• what happens when an enzyme denatures


  the substrate doesnt fit into the active site
• what is the central nervous system


  consists of the brain and spinal chord, responsible for processing information and giving out instructions.
• what is the peripheral nervous system


  consists of neurones, receptor cells and effectors. it is responsible for collecting information, sending it to the central nervous system and acting on instructions from the cns
• what does a relay neurone do


  messages within the central nervous system are passed by short relay neurones. they connect the sensory neurones to the motor neurones
• what does a motor neurone do


  carry nerve impulses away from the central nervous system, the neurone either ends in a muscle or gland which are effectors.
• what is a sensory neurone


  carry electrical signals-nerve impulses-towards the nervous system.
• electrical impulses cannot pass over gaps, so the signal must change to a chemical impulse to pass.
• how does the body regulate its internal environment


  • electrical impulse triggers vesicles to move to the synapse membrane.
  • vesicles fuse with the membrane and releases neurotransmitters into the synapse.
  • neurotransmitter diffuses across the synapse and binds to receptors on the other side.
  • once enough receptors have neurotransmitters bound to them, the signal is transmitted.
• reflex arc


  stimulus-receptor-coordinator-effector-response
• describe the reflex arc


  • receptor in the skin detects a stimulus
  • sensory neurone sends electrical impulses to a relay neuron, which is located in the spain chord of the CNS. relay neurons connect sensory neurons to motor neurons
  • motor neuron sends electrical impulses to an effector
  • effector produces a response
• what is a stimulant


  speeds up neurotransmitters
• what is a depressant


  slow neurotransmitters down
• what is reaction time


  the time it takes for a person to respond to a change.
• reaction time practical


  • iv: amount of practice
  • dv: reaction time
  • cv: where the forefinger is positioned
• reaction time practical


  • use non-dominant hand
  • sit upright with eyes looking across the room
  • place forehand on table
  • partner hold a ruler with the bottom of the ruler (0cm) between thumb and finger.
  • partner drop the ruler without telling you
  • catch it as fast as you can
  • look at the cm at the top of your thumb
• hormones- chemical messangers


  • regulate functions of many organs and cells
  • coordinate processes in body
  • are secreted (produced) from glands into blood stream
  • travel in blood to target organs
  • are detected by receptors in cells within target organs
  • the body usually responds slowly to hormones, can often coordinate long term bodily changes
• which organ makes insulin


  pancreas
• what happens if a person cannnot regulate blood sugar levels


  diabetes is a condition where the blood glucose levels remain too high. it can be treated by injecting insulin. the extra insulin causes the liver to convert glucose into glycogen, which reduces the blood glucose level.
• what happens if a person cannnot regulate blood sugar levels


  diabetes is a condition where the blood glucose levels remain too high. it can be treated by injecting insulin. the extra insulin causes the liver to convert glucose into glycogen, which reduces the blood glucose level.
• type 2 diabetes


  the persons body cells can no longer respond to insulin produced by the pancreas, it is more common in older people. it can be controlled by a carbohydrate-controlled diet and an exercise regime. carbohydrate is digested into glucose, which raises the overall blood glucose level.
• what is type 1 diabetes


  where the pancreas fails to produce enough insulin, can be controlled by injecting insulin.
• pituitary gland 


  a gland that secretes several hormones into the blood in response to the bodys condition.
• glucagon


  a hormone produced when the blood glucose concentration is too low. causes glycogen to be converted into glucose and released into the blood.
• glycogen


  a storage molecule made from many glucose molecules bonded together, found in muscle and liver cells.
• thyroxine


  hormone produced by the thyroid gland. thyroxine stimulates the metabolic rate, important in growth and development
• adrenaline


  hormone produced by the adrenal glands in times of fear/stress. it increases the heart rate and boosts the delivery of oxygen and glucose to the brain and muscles, preparing the body for fight or flight.
• endocrine system


  the system of glands that secretes hormones
• ovulation


  the release of an egg cell, occurs approximately every 28 days
• FSH


  produced by pituitary gland, a hormone that causes an egg to mature in the ovary, causes oestrogen to be produced
• oestrogen


  produced by the ovaries, causes blood lining of uterus to develop. stops FSH being produced, stimulates release of LH
• LH


  produced by pituitary gland, hormone that causes ovulation
• progesterone


  produced by the ovary, maintains blood lining in uterus, stops production of LH and FSH
• oral contraceptives


  the contraceptive pill, contains hormones to inhibit FSH production so eggs to not mature.