Homeostasis

Homeostasis

Nervous System
1. Central Nervous System (CNS)
  1. Brain
    1. Parts of the brain
      1. Hypothalamus
        Helps regulate body temperature
        Helps the body realise hunger and thirst
        Plays a role in emotions
        Releases and controls many hormones that the body needs to function
      2. Pituitary gland
        Regulates and releases important hormones to our body
        Plays a big part in the body's overall wellbeing
      3. Brain stem
        Breathing
        Heart rate
        Blood pressure
        Swallowing
        PLays a role in alertness and sensation
      4. Cerebrum
        Divided into two hemishperes
        Largest part of the brain
        Controls all conscience activities
      5. Cerebellum
        Responsibles for movement, balance and coordination
        Allows us to stand upright, keep our balance and move around
      6. Frontal Lobe
        Planning and organising
        Problem solving and decision making
        Memory and attention
        Controlling behaviour, emtions and impulses
        Left frontal lobe plays a large role in speech and language
      7. Temporal Lobe
        Recognizing and processing sound
        Understanding and producing speech
        Various aspects of memory
      8. Occipital Lobe
        Receives and processes visual information
        Contains areas that help in perceiving shapes and colours
      9. Parietal Lobe
        Intergrate sensory information from various parts of the body and contains primary sensory cortex, which controls sensation (hot, touch, cold, pain)
        Tells us which way is up and helps keeping us from bumping into things when we walk
  2. Spinal cord
2. Peripheral Nervous System
  1. Somatic Nervous System
    1. Controls voluntary muscle movements
      1. e.g. waving, chewing, swallowing, movement
      2. Coordinates movements of the body
    2. Deals with external stimulus
    3. Collects information from sensory organs
  2. Autonomic Nervous System
    1. Sympathetic Nervous System
      1. Fight or flight
      2. Speeds up body functions and makes them work more efficiently - its in control when you are active
    2. Parasympathetic Nervous System
      1. Rest and digest
      2. Slows down body functions - is in control when you're resting
    3. Controls involuntary action which maintain homeostasis e.g. digestion, heartbeat
  3. Makes up all nerves outside the CNS
  4. Carries information to and from CNS to the rest of the body
3. Neurons
  1. Different types of neurons
    1. Motor Neurons
      1. Carries messages to the effector (glands and muscles) which creates the response
    2. Sensory Neurons
      1. Carries messages from the sense organs to the brain and spinal cord.
    3. Inter/ connector neurons
      1. Makes connections in nerve pathways
  2. Parts of a neuron
    1. Dendrites
      1. Receives information from other cells
    2. Cell body
      1. Contains nucleus, vacuole, mitochondria etc.
    3. Axon
      1. Transfers the electrical messages
    4. Myelin Sheath
      1. Insulates the electrical signal in the axon and protects the nerve cells in the axon - it is made of fat and increases the speed of the nerve impulse
    5. Axon terminal
      1. Passes the message/ signal onto the synaptic cleft
    6. Synaptic cleft
      1. Neurotransmitters transmit the electrical signal across the gap
  3. Neurons have a fast electrical signal called a "nerve impulse"
Endocrine System
1. Bloodstream
2. Produces hormones in endocrine glands
  1. Hormones bind to specific receptors on cells
    1. Those cells are called target cells
Immunity
1. Pathogens
  1. Types of pathogens
    1. Bacteria
    2. Fungi
    3. Viruses
    4. Protozoa
    5. Worms/ parasites
  2. Cause sickness - are infectious
  3. Transmission
    1. Direct contact
      1. e.g. Coughing/ sneezing/touching someone when you are sick
    2. Indirect contact
      1. e.g. Sick person touching a door handle and then someone else touching the handle
    3. Contamination
      1. Food poisoning
      2. Contaminated water
2. Immunisations
  1. People get injections that hold deformed or dead pathogens
  2. The immune response to pathogens is faster after immunisations
3. The three lines of defense
  1. Third line (specific)
    1. Specific
    2. Lymphadic system
    3. Lymphocytes (T and B cells)
      1. Located in lymph nodes
    4. T and B cells are activated by an antigen
      1. T cells kill the infection
      2. B cells release antibodies
      3. The T and B cells clone themselves to help kill the infection - thus the lymph nodes becoming swollen
      4. Antibodies are released
        The antibodies stick to the antigens and clump bacteria together for the macrophages to eat
        After this the T and B cells form memory cells - these remember how to fight the pathogen the next time it infects the body
  2. Second line (innate)
    1. Non - specific
    2. Inflammation
    3. Neutrophils and macrophages
      1. They form pus when they die
      2. They engulf bacteria, break them down and kill them
  3. First line
    1. Purpose is to stop pathogens getting into the body
    2. Non - specific
    3. Parts of the body in the first line
      1. Saliva
      2. Skin
      3. Eyelashes
      4. Mucus
      5. Stomach acid
      6. Tears
Respiratory System
1. Diffusion
  1. The movement of particles from a high concentration to a low concentration.
2. Breathing
3. Gas exchange
  1. Alveoli - they are located on the lungs and have many features that help with diffusion
    1. Only one cell thick
    2. Covered in capillaries
    3. Moist membranes so gases can dissolve more easily
    4. Moves oxygen into the blood and takes CO2 (carbon dioxide) out of the blood
Digestive System
1. Includes breakdown of lipids and fats
2. The characteristics and features of villi help with efficient diffusion of nutrients
  1. The nutrients - proteins, glucose and lipids - then go to the bloodstream
  2. Only one cell thick
  3. Surrounded by blood capillaries
  4. They are located in the small intestine
  5. Villi have micro- projections on them that allow a bigger surface area
3. Breaking down foods
  1. Mechanical Breakdown
    1. Chewing
  2. Chemical Breakdown
    1. Enzymes
Metabolism
1. Chemical processes
2. Cellular respiration
3. Glucose + oxygen (O2) = carbon dioxide (CO2) + energy + water (H2O)

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	Created by Alice Price over 6 years ago