Control and Co-ordination

• The medulla oblongata regulates automatic body processes like breathing, heartbeat, and blood pressure.
• Living organisms respond and react to changes in the environment, which are called stimuli
• Plants and animals respond to stimuli in different ways
• Control and coordination in animals is done through the nervous system and endocrine system
• Receptors are specialized tips of nerve fibers that collect information to be conducted by nerves
• Phono-receptors are in the inner ear for hearing and balance

  <|>Photo-receptors are in the eye for visual stimulus

  <|>Thermo-receptors in the skin are responsible for pain, touch, and heat stimuli

  <|>Olfactory-receptors in the nose receive smell

  <|>Gustatory-receptors in the tongue help in taste detection
• The nervous system is composed of nervous tissue and neurons are its functional units
• Neurons consist of cyton or cell body, dendrites, axon, axon terminals, and myelin sheath

  <|>Types of neurons include sensory neurons, motor neurons, and association or relay neurons
• Synapse is the point contact between the terminal branches of axon of one neuron with the dendrite of another neuron
• The human nervous system consists of the central nervous system, peripheral nervous system, and autonomous nervous system
• Central Nervous System includes the brain and spinal cord

  <|>Peripheral Nervous System includes cranial nerves and spinal nerves

  <|>Autonomous Nervous System includes sympathetic and parasympathetic nervous systems
• The human brain is divided into forebrain, midbrain, and hindbrain
• Forebrain consists of the cerebrum

  <|>Midbrain consists of the hypothalamus

  <|>Hindbrain consists of the cerebellum, pons, and medulla oblongata
• Cerebrum controls voluntary motor actions, sensory perceptions, learning, and memory
• Hypothalamus controls sleep-wake cycle, eating, and drinking urges
• Cerebellum coordinates motor functions, posture, balance, and precision of voluntary action
• Medulla controls involuntary functions like heartbeat and respiration
• Pons relays impulses between lower cerebellum and spinal cord, and regulates respiration
• Spinal cord controls reflex actions and conducts messages between body parts and brain
• Reflex action is an involuntary movement in response to a stimulus, controlled mainly at the level of the spinal cord
• Brain is protected by meninges and cerebrospinal fluid, while the spinal cord is enclosed in the vertebral column
• Muscle contractions are triggered by nerve signals, involving actin and myosin filaments sliding towards each other
• Endocrine system consists of endocrine glands that secrete hormones directly into the bloodstream
• Hormones are mainly composed of protein and assist the nervous system
• Endocrine gland secretes its product directly into the bloodstream
• Hormones are mainly composed of protein
• Hormones assist the nervous system in control and coordination
• Hormonal control is somewhat slower than nervous control
• Hormones are chemical messengers secreted in small amounts by ductless glands
• Hormones act on target tissues/organs away from their source
• Endocrine System helps in control and coordination through hormones
• Pituitary gland (master gland):

  • Location: at the base of the brain
  • Hormones produced: Growth hormone (GH), Thyroid stimulating hormone (TSH)
  • Functions: GH stimulates growth, TSH stimulates thyroid gland functioning
• Follicle stimulating hormone (FSH):

  • Location: not specified
  • Function: stimulates follicles during ovulation
• Thyroid Gland:

  • Location: neck
  • Hormone produced: Thyroxine
  • Function: controls general metabolism and growth
• Adrenal gland:

  • Location: above kidneys
  • Hormone produced: Adrenalin
  • Function: prepares the body for emergency situations
• Pancreas:

  • Location: near stomach
  • Hormone produced: Insulin
  • Function: controls blood sugar level
• Testis (male):

  • Location: in scrotum
  • Hormone produced: Testosterone
  • Function: sperm production, development of secondary sexual characters
• Ovary (female):

  • Location: near uterus
  • Hormone produced: Oestrogen
  • Function: egg production, development of secondary sexual characters
• Importance of iodised salt:

  • Iodine is essential for thyronine hormone
  • Iodised salt is important for thyroid gland to control metabolism
  • Deficiency of iodine can cause goitre
• Diabetes:

  • Cause: deficiency of insulin hormone
  • Treatment: administer injections of insulin hormone