B1.2 - Coordination and Control

?
View mindmap
  • B1.2 - Coordination and Control
    • 2.1
      • The nervous system allows humans to react to their surroundings and coordinates behaviour.
      • Receptors detect external stimuli.
      • Electrical impulses pass to the brain along neurons.
      • The brain coordinates responses.
      • The brain and spinal cord form the central nervous system (CNS).
        • Nerves contain neurons.
          • Sensory neurons carry impulses from receptors to the CNS.
        • Motor neurons carry impulses from the CNA to the effector organs (muscles or glands).
          • The muscles respond by contracting.
            • The glands respond by secreting (releasing chemicals).
    • 2.2
      • Reflex actions are rapid, automatic responses to a stimulus.
      • Reflexes protect us from damage.
      • A receptor detects a stimulus (sharp pain).
        • a sensory neuron transmits the impulse to the CNS.
          • A relay neuron passes the impulse on.
            • A motor neuron is stimulated.
              • The impulse passes to an effector (muscle or gland).
                • Action is taken (the response).
      • At the junction between 2 neurons is a synapse. Chemicals transmit the impulse across the gap.
        • The sequence from receptor to effector is a reflex arc.
    • 2.3
      • The menstrual cycle takes 28 days,  wit ovulation about 14 days into the cycle.
      • The cycle is controlled by 3 hormones.
      • Follicle stimulating hormone (FSH) is made by the pituitary gland and causes the egg to mature and oestrogen to be produced.
        • Oestrogen is produced by the ovaries and inhibits (stops) the further production of FSH.
          • It stimulates the production of LH and stimulates the womb lining to develop to receive the fertilised egg.
          • Luteinising hormone (LH) is made by the pituitary gland and stimulates the mature egg to be released from the ovary (ovulation).
    • 2.4
      • The contraceptive pill (oral) contain oestrogen and/or progesterone to inhibit FSH.
        • Progesterone only pills have fewer side effects.
      • The contraceptive pill prevents the production of FSH so no eggs mature.
      • If a woman cannot produce mature eggs, FSH and LH can be given.
        • This is known as fertility treatment.
          • FSH causes eggs to mature. LH stimulates ovulation.
    • 2.5
      • The body controls its internal environment.
        • Internal conditions controlled are:
          • Water content.
            • Ion content.
              • Temperature.
                • Blood sugar level.
      • The nervous system and hormones help keep the internal conditions to a limit.
    • 2.6
      • Plants respond to light, gravity and moisture.
      • Shoots grow towards light and away from gravity.
        • Roots grow towards gravity and water.
          • Gravitropism.
        • Plant shoots grow towards light.
          • Phototropism.
      • Auxin is the hormone which controls phototropism and gravitropism.
        • Unequal distribution of auxin causes unequal growth.
        • Plant hormones have uses in agriculture and horticulture.
    • 2.7
      • Advantages
        • To become pregnant.
        • Kill unwanted plants.
        • Prevent unwanted pregnancies.
        • Encourage fruit to ripen.
      • The incorrect use of plant hormones can damage the environment.
      • Disadvantages
        • Damage to environment.
        • Side effects in women.

Comments

No comments have yet been made

Similar Biology resources:

B4
B1
See all Biology resources »See all Nervous system, hormones and behaviour resources »