Response and Regulation

• Sensory Organs What do your body sense? 


  Eye- Light

  Ears- Sound

  Skin- Touch and Temperature

  Nose and Tongue- Chemicals
• What a Neutron?

  Are individuals nerve
• What an nerves?

  Bundles or neurones surrounded by connective tissue and blood vessels
• The 3 types of neurones

  • Sensory- carries impulses from receptors (sense organs) to the CNS
  • Relay- Carries impulses from the sensory neurone to the motor neurone in the CNS
  • Motor- Carries impulses from the CNS to effectors (muscle and glands)
• What are the 2 main part of the nervous system

  • Central nervous system
  • Peripheral nervous system
• Nervous system

  It is made up of the brain and spinal cord (CNS) along with specialised nerve that carry information as impulses into and out of the CNS
• What does the Nervous System control?

  Movement by sending electrical impulses (nerve impulses) along a network of specialised nerve cells know as neurone as this allows an organism to rapidly react to environment and internal change
• Reflex actions

  Is a fast and automatic response to a stimulus. It is involuntary (does not involve the conscious part of the brain) and serves as a protective mechanism
• Examples of Reflex actions

  • Withdrawal reflex- pulling away, initiated when touching a hot object to prevent burns
  • Pupil reflex- pupils constrict to prevent damage to the eye by bright light
  • Blink reflex- protects eye from the foreign bodies
• The pathway of a reaction?

  1. Stimulus (pain from sharp object)
  2. Receptors (pain receptors in skin)
  3. Sensory Neurone sends message to the brain
  4. Brain sends message along
  5. Motor Neurone sends message to muscle
  6. Muscle in arm
  7. Pulls hand away
• What a reflex action?

  Is a fast and automatic a the signal does not go through the brain. They are designed to protect us from harm
• What a reflex arc?

  Is a nerve pathway involved in a reflex action
• Pathway of a reflex arc

  1. Stimulus
  2. Receptor
  3. Coordinator
  4. Effector
• How does a reflex pathway differ from a normal nervous system pathway?

  I’d does not go through the brain as it is a reflex
• Define a reflex action

  MEMORIES THIS DIAGRAM!!!!!!!!

  
• What does homeostasis?

  Is the regulation of the internal conditions of a a cell or organism to maintain optimum conditions for function in response to internal and external change
• Meaning of the word homeostasis

  Homeo is the Greek word for similar

  Stasis is the Greek word for stable
• Things that need to be kept constant inside the body for it to function properly

  • Temperature
  • pH
  • Blood glucose levels
  • Mineral ions
  • Water
• Metabolism

  Operates only within a narrow range of temperatures and pH and requires appropriate nutrients and water
• Hormones

  Is a cell signalling molecules produced by the endocrine glands and released into the blood. It travels to a target organ and binds, initiating a response
• The control of blood glucose concentrations

  Blood glucose concentration must be controlled

  • If it rises to high the body risks dehydration
  • If it becomes to low the rate of cellular respiration decreases
• What is blood concentration controlled by?

  Hormones insulin and glycogen which are sec related by the pancrease
• Hormones- Insulin

  Effect-

  • Cause liver and muscle cells to increase their uptake of glucose
  • Glucose is converted to glycogen a storage moelcule
• Hormones - Glycogen

  Effect-

  • Causes the breakdown of glycogen to glucose in the liver
  • Glucose is released into the blood
• What is the endocrine system?

  A system of glands that produce and secrete hormones into the bloodstream to regulate various bodily functions.
• Why do we need to maintain a constant body temperature of 37 degrees

  Body reaction need enzymes to work. Our enzymes have an optimum temperature of 37 degrees
• Negative Feedback


  Is a corrective mechanism that allows only small fluctuations around a set point.
• What happens when blood glucose concentration increases above a set point?

  • Pancreas secrets insulin and stops producing glucagon
  • Liver cells convert glucose to glycogen which is stored
  • Blood Glucose concentration decreases returning to normal level
• What happens when blood glucose concentration decreases below a set point

  • Pancreases secretes glycogen and stops producing insulin
  • Liver cells convert glycogen into glucose which is released into the blood
  • Blood glucose concentration increases returning to normal level
• Diabetes

  Is a condition where the homeostatic control of blood glucose levels stops working
• Diabetes Type 1

  Causes- Immune system attacks and destroy insulin produces cells due pancreas does not produce enough insulin

  Treatment- Daily insulin injection at meal time, Managing diet (limiting refines sugars), regular testing of blood and glucose
• Diabetes Type 2

  Cause- Person develops insulin resistance (links to obesity)

  Treatment- Managing a healthy diet, Regularly exercise, Drugs
• The control of body temperature is an example of negative feedback

  1. Temperature increases above 37 degrees
  2. Vasodilation: Dilation of blood vessels near skin surface. Blood flows closer to the skin surface because there a greater heat loss to surroundings
  3. Sweating heat energy used to evaporate sweat. Increase heat transfer from skin to environment due body temp decreases
  4. Erector muscles hair lye flat
  5. No shivering
• The control of body temperature is an example of negative feedback

  1. Temperature decreases below 37 degrees
  2. Vasoconstriction: Constriction of blood vessels, near skin surface. Less blood flows close to skin surface due reduced heat loss to surrounding
  3. Little sweat is produced
  4. Erector muscle contrast Hairs stand on end creating pockets of air beneath hairs and a layer of insulation
  5. Shivering: Involuntary contraction of muscles generates heat energy from respiration
• Diagram of the skin

  Diagram

  
• Temperature control is an example of negative feedback what does that mean?

  Level of something rises, control system reduces it again, if levels of something falls control system it raises it again
• Lifestyle Choices

  • Obesity increases the risk of type 2 diabetes
  • Drugs affect chemical processes within the body and can produce damaging side effect and lead to addiction
  • Alcohol decreases reaction times and causes liver damage cardiovascular disease