bio

• Epithelial Tissue

  • squamous
  • columnar, ciliated
  • cuboidal
  • stratified (layered)
• MAMMALIAN TISSUES

  • Connective Tissue
  • Muscle Tissue
  • Nerve
• Connective Tissue


  • Proper
  • Liquid
  • Supporting
• Liquid Connective Tissue

  • Blood
  • lymph
• Muscle Tissue

  • voluntary striated
  • involuntary, smooth
  • cardiac
• Muscle tissue is made of cells with projections that contract
• Nerve tissue is made of cells with projections that transmit electrical signals
• Blood is a connective tissue made up of cells in a fluid
• Areolar Connective Tissue

  • It consists of a jelly-like matrix, with a network of long branched white collagen fibres, and a non-elastic structure formed by the flat connective tissue cells
  • It occurs between the skin and underlying tissues. It is the tissue that binds skin to the body
  • When areolar connective tissue contains fat it is known as adipose tissue, or simply fatty tissue
• White blood cells are produced by the red marrow, spleen and lymph glands and play an important role in the immune system
• Haemoglobin

  A protein with four iron-containing haemic groups to which oxygen molecules can bind temporarily. This is the pigment responsible for the red colour of blood.
• Haemoglobin can be an indicator, as oxyhaemoglobin has a bright red colour and carbaminohaemoglobin has a dark red colour.
• White blood cells contain much less of them, never more than 1% of the blood corpuscles (about 10 000 to 12 000 per cubic millimeter)
• The life span of white blood cells is short, for some only a few days or even hours
• Haemoglobin


  A protein with four iron-containing haemic groups to which oxygen molecules can bind temporarily. This is the pigment responsible for the red colour of blood
• Haemoglobin is pigment (content) that gives blood its red colour. Oxyhaemoglobin has a bright red colour and carbaminohaemoglobin has a dark red colour. In this way haemoglobin can be regarded as an indicator of the oxygen content of the blood
• Blood platelets


  Small discs without nuclei that resulted from the break-up of bigger cells. These cells are present in blood-producing tissues
• Blood clot formation


  1. Blood platelets group themselves around the edges of the wound

  2. Platelets secrete substances that attract more platelets

  3. Fibrinogen turns into fibrin

  4. Fibrin fibres form a gauze-like network over the wound, trapping blood cells and platelets
• Vitamin K is necessary to produce some of the more than thirty substances involved in the clotting of blood
• Blood transfusions should be done with the right blood type to avoid incompatibility reactions
• If a Rhesus negative mother has a Rhesus positive baby, the mother can develop antibodies that can cause problems in future pregnancies
• Haemolytic disease of the newborn can occur if the mother's antibodies cross the placenta and destroy the baby's red blood cells
• Voluntary muscle tissue


  • Controlled by a conscious decision
  • Has cross-striated appearance under the microscope
• Involuntary muscle tissue


  • Functions automatically and is not controlled by a conscious decision
  • Fibres do not exhibit any striation
• Cardiac muscle tissue


  • Differs in many ways from voluntary and involuntary muscle tissues
  • Is also an involuntary muscle tissue
• Cross-striated muscle fibres


  • Long cylindrical fibres bound together in bundles
  • Enclosed by a membrane called the sarcolemma
  • Have multiple nuclei situated just below the sarcolemma
  • Consist of groups of fibrils with darker and lighter areas, giving the fibre its characteristic striated appearance
• Muscle fibres are served (innervated) by motor neurons, and one such neuron can serve more than one muscle fibre. This promotes coordinated movement
• Muscle fibres are bound into larger bundles and the larger bundles, in their turn, form a muscle. Bundles are enclosed by a connective tissue membrane, the perimysium. The whole muscle is enclosed by the epimysium
• Blood vessels occur in the connective tissue surrounding larger muscle bundles as well as in the muscles. Capillary blood vessels bring individual fibres in contact with blood
• Multipolar neurons


  • Have one axon, but many dendrites. This means that they can make contact with many other neurons
• Drugs such as alcohol increase the synaptic gap and the transfer of a message takes place much more slowly than normal, resulting in slower movements and a slower reaction to stimuli. The secretion of neurotransmitters is also inhibited by some substances, with a slower reactions as a result
• Reflex actions


  Protect your body against injuries, such as blinking, involuntary kicking when hit on the knee, pulling away when touching a hot stove plate
• Types of neurons


  • Bipolar neurons have one dendrite and one axon
  • Unipolar neurons have one outgrowth that splits into a T, with an afferent (dendrite) and efferent (axon) outgrowth
  • Motor neurons take impulses from the central nervous system to the effectors or muscles or glands
  • Sensory neurons receive impulses from the senses, and take them to the central nervous system where they are processed
  • Interneurons occur inside the central nervous system, and are also known as connector neurons
• Afferent outgrowths, axons and other structures move towards a structure eg, all body central nervous system/organ
• Efferent outgrowths, neurons move away from these structures
• Myelin sheath


  Improves the speed of impulse transmission along the axon