Co ordination
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Co ordination






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Co ordination Co ordination Presentation Transcript

  •  all organs and systems in a healthy human body are co-ordinated  co-ordinated means :  they co-operate with one another and work together efficiently
  •  Consider the tennis player about to hit the ball: Physical activity is one function that requires co-ordination 1 Eyes see ball. 2 3 Information goes to brain & is processed. Brain sends messages to muscles to hit the ball.
  • Co-ordination of body functions involves:
  • Brain & Spinal cord:  the main parts of the NS  are called the CNS
  • Vertebrae protect the spinal cord Spinal cord Vertebra Vertebral column
  • How is the CNS connected to the various parts of the body?
  • The Nervous System receives messages from: Sense organs CNS
  • The Nervous System sends messages to:  Muscles  Glands Effectors CNS Salivary glands
  • Flow of information What are ‘stimuli’?
  • A stimulus is:  a change in the environment that can be detected by a sense organ and brings about a response
  • Stimuli [stimulus = singular] Cold Heat Sound Chemicals in air Pain
  • Neurones and nerves Neurone = nerve cell Nerve = a bundle of nerve cells neurones
  • Neurones can be very long
  • Sensory neurones Motor neurones Intermediate or Relay neurones Three types of Neurone
  • Structure of a sensory neurone
  • Function of the myelin sheath to insulate the fibre speeds up the impulses Myelin sheath: FAT
  • Direction of impulse along a sensory neurone Axon carries impulse: Away from the cell body
  • Fig. 4 A motor neurone. [axon terminal] Direction of impulse
  • Differences in structure between a: 1. Long axon 2. No receptor 3. Cell body terminal & has dendrites 4. Many short dendrons 1. Short axon 2. Receptor 3. Cell body at the side; no dendrites 4. One long dendron receptor axon axon dendron Sensory neuroneMotor neurone C N S C N S
  • Differences in function between a: receptor Sensory neuroneMotor neurone C N S C N S Carries the impulse towards the CNS Carries the impulse away from the CNS
  • Fig. 5 Connections between a sensory, a relay and a motor neurone.  Neurones DO NOT touch each other Sensory neurone Motor neurone Relay neurone
  • A synapse is a tiny gap between neurones synapse
  • Impulses travel in direction across a synapse Sensory neurone Motor neurone Relay neurone Effector Receptor
  • How many synapses on one cell body? 1,000 to 10,000!!
  • Fig. 6 A synapse.
  • A Reflex Action is a  rapid, automatic, involuntary response to a stimulus
  • Examples of reflex actions:  Sneezing
  •  Blinking  Coughing  Removing the leg when stepping on a pin
  • Examples of reflex actions:  withdrawing your hand from a hot object
  • Why are reflex actions useful to the body?
  • Question: SEP 2010 1. What is the main function of the nervous system? (2) The NS contains a network of specialised cells called neurones that coordinate the actions of an animal and transmit signals between different parts of its body.
  • b. List the stimulus and response for each of the following reflex actions: i. swallowing; (3) Stimulus: food in mouth Response: food goes down oesophagus ii. coughing. (2) Stimulus: foreign particles in trachea Response: removal of foreign object from trachea
  • Question: MAY, 2011 [2B] A student accidentally touches a beaker of hot water. The student pulled her hand away from the hot water very quickly. This is an example of a reflex action. a) Define the term reflex action. (2)
  • Question: MAY, 2011 [2B] b) List TWO examples of reflex actions taking place in newborn babies. (4) Suckling reflex Grip reflex Stepping reflex Crying reflex
  • The reflex arc is:  the path along which a nerve impulse travels from the receptor to the effector  e.g. :  Knee jerk reflex arc  The hand withdrawal reflex arc
  • The knee jerk is a reflex action
  • The knee jerk reflex arc MuscleSpinal cord
  • Dorsal [back] TS spinal cord Ventral [front]
  • A sensory neurone always enters via the DORSAL ROOT
  • Dorsal root ganglion is a collection of cell bodies of the sensory neurones
  • Fig. 7 The hand withdrawal reflex arc.
  • Myelin = FAT = white Grey matter White matter TS spinal cord Why is the white matter white?  due to nerve fibres covered by myelin
  • Grey matter White matter  due to nuclei present in cell bodies TS spinal cord Remember nuclei look DARK. Why is the grey matter grey?
  • Question A transverse section through the spinal cord is examined under the high power of the microscope. Part of it looks like diagram A and part looks like diagram B. Which is grey matter and which is white matter? Give reasons for your decision. A B
  • Answer Diagram A represents nerve fibres cut in cross- section and therefore comes from white matter. Diagram B shows many cell bodies which constitute much of the grey matter. A B
  • Label the diagram. Draw arrows to show direction of impulse A – receptor B – sensory neurone C – motor neurone D – synapse
  • Question: SEP, 2004 6d) The following diagram demonstrates the rapid and automatic removal of a finger from a flame. i) Complete the diagram by drawing and naming the neurones that bring about this reflex action.
  • ii) Use arrows to show the pathway of the nerve impulse along the neurones. (4)
  • e) Some individuals suffer from a motor neurone disease in which the neurones gradually degenerate. How is this likely to interfere with the efficiency of reflex actions? (2) Reflex actions take longer to occur – they become less efficient.
  • Label the two neurones. What is the function of each?
  • Question: SEP 2010 Draw a labelled diagram showing the reflex arc that takes place in a knee jerk reflex. On the diagram indicate clearly the direction of flow of impulses. (You are not expected to draw the muscles involved or the spinal cord). (6)
  • Question: MAY, 2011 [2A] A student accidentally touches a beaker of hot boiling water. The student pulled away her hand within a few milliseconds. This is an example of a reflex action. a) Write a brief description about the events leading to the student pulling away her hand. (5) b) Draw a diagram showing the reflex arc responsible for producing this reflex action. In your diagram include arrows to show the direction of nerve impulses travelling along the neurones. (6)
  • The skull protects the brain
  • The cerebrum is highly folded Many neurones can be packed into a small space.
  • Two Cerebral hemispheres = cerebrum
  • The cerebrum  controls our:  sensations  movements  is responsible for:  memory  thought  intelligence Cerebrum
  • The cerebrum contains 2. Sensory areas:  for sensation 1. Motor areas:  for movement 3. Association areas :  for thinking
  • Parts of the brain: Cerebrum / cerebral hemisphere Cerebellum Medulla oblongata Pituitary gland Hypothalamus
  • Functions of:  releases hormones  homeostasis
  • Functions of the cerebellum:  controls balance and muscular co-ordination
  • Functions of the medulla oblongata:  controls various automatic processes such as:  the rate of breathing  heartbeat
  • Functions of the cerebrospinal fluid: 1. acts as a shock absorber 2. to allow oxygen and nutrients to diffuse through it to nourish neurones 3. to allow removal of wastes
  • Meninges  are layers of tissue that surround the CNS
  • Meningitis  is an infection of the meninges
  • Question: SEP 2010 1. List the function of each of the following parts within the central nervous system: i. cerebrum; (2) ii. cerebellum; (2) iii. medulla oblongata. (2) 2. In humans the cerebrum is very large and highly folded. Explain why. (2)
  • Glands in the body are: secrete an enzyme into a duct  secrete hormones  have no duct (ductless)  have a rich blood supply Exocrine gland Endocrine gland
  • What is a hormone?  a chemical which is produced by one part of the body, travels in the bloodstream and has an effect on the target organ
  • Fig. 14 Position of the main endocrine glands in the human body.
  • The main human endocrine glands and their secretions. Gland Hormone Function Thyroid Thyroxine Controls the metabolic rate
  • Gland Hormone Function Adrenals Adrenaline Prepares the body for action Kidneys Adrenal glands
  • Adrenaline, the emergency hormone
  • Adrenaline prepares the body for action Muscles need ENERGY to contract!!
  • Which process releases energy? glucose + oxygen carbon dioxide + water + energy glucose oxygen muscle energy How can MORE glucose + oxygen reach the muscle?
  • Effects of adrenaline Heart beat increases Breathing rate increases
  • Effects of adrenaline  Arteries to muscles widen What is the effect of this?
  • 5 litres of blood in an adult If more blood flows to muscles less must flow to other organs. Which?
  • Gut & Skin get less blood  As arteries narrow A person becomes pale when afraid. Why?
  • Glycogen Glucose in the blood increases Glycogen is converted to glucose Effects of adrenaline
  • Effects of adrenaline include: 1. Heart beat increases 2. Breathing rate increases 3. Arteries to gut and skin narrow 4. Arteries to muscles widen 5. The pupils of the eyes widen 6. Glycogen is converted to glucose
  • Gland Hormone Function Pancreas Insulin Decreases the blood sugar level Glucagon Increases the blood sugar level
  • Control of blood sugar
  • Question: MAY, 2011 Give a biological explanation for the following situation: A diabetic person received an insulin shot after intake of a meal rich in carbohydrates. (2) A diabetic person does not produce insulin. The insulin injected helps the person to reduce the sugar level in the blood back to normal.
  • Gland Hormone Function Ovaries Female sex hormones e.g. oestrogen Control sexual development Testes Male sex hormones e.g. testosterone Control sexual development
  • Gland Hormone Function Pituitary Growth hormone Speeds up growth FSH Causes follicle to develop into a Graafian follicle LH Causes ovulation ADH Causes kidneys to reabsorb water
  • Differences between nervous and endocrine co-ordination. Nervous Chemical Information passes as electrical impulses along nerve fibres Information passes as a chemical substance through the bloodstream Rapid transmission Slow transmission Response is immediate Response is usually slow e.g. growth Response is short-lived Response is long-lasting Response is very exact Response is usually widespread
  • Negative feedback control:  produces an effect which is the opposite of what has been happening before  e.g. if body temperature rises, sweat is produced to cool it down  is important to keep conditions constant in the body
  • Control of blood sugar as an example of: NORM Excess Deficiency Corrective mechanism Corrective mechanism NORM Negative feedback Negative feedback