BMAT biology

Nota:

• muscular tissue/ glandular tissue/ epithelial tissue

1. Digestive System
   1. carbohydrates- salivary amylase to disaccharides and then monosaccharides
   2. Proteins- pepsin, trypsin, chymotrypsin are proteases. In stomach
   3. Fats- (emulsified by bile salts) + lipase
   4. digestive tract is lubricated with mucus to protect from digestive enzymes
2. Respiratory System
   1. Air Pathway

      Nota:

      • Nose-nasal cavity-pharynx-larynx-trachea-bronchi-bronchioles-alveoli
   2. Mechanics of pulmonary ventilation
   3. External Respiration- exchange of oxygen and carbon dioxide in the lungs- know what factors make lungs good site for gas exchange
   4. During exercise glycogen is used. glucose from food is stored as glycogen in the liver and muscle cells
   5. Artificial ventilators
3. Circulatory System
   1. RBC adaption
   2. Atrial systole/ ventricular systole, diastole
   3. Comparison of blood vessels
      1. arteries
      2. Veins
      3. Capillaries
   4. clot= mesh of fibrin fibres
      1. reaction- platelets exposed to damaged vessel
   5. blood transfusions- RBC either have A or B antigens (or neither or both)
      1. Plasma can contain anti A or anti B antibodies
      2. if an A antigen meets an anti A antibodies causes agglutination (v bad)
      3. blood group is important
   6. Electrical control of heartbeat
      1. 1SAN
      2. 2AVN
      3. 3Bundle of His/ Purkinje fibres
4. Nervous System
   1. Sense Organs detect Stimuli
      1. Contain receptors- change stimulus energy into electrical impulse
   2. CNS coordinates response

      Nota:

      • brain and spinal cord
      1. Neurons transmit information to and from CNS
         1. Impulse passed along axon- cytoplasm fibre surrounded by cell membrane

            Nota:

            • some axons surrounded by fatty sheath to insulate
            1. dendrites connect to other neurones
         2. Sensory- long dendrite impulse from receptor to cell body- short axon carries impulse from cell body to CNS

            Nota:

            • receptor to CNS
            1. Relay- Lots of short dendrites carry impulse from sensory n. to cell body, many short axons carry impulses from cell body to motor neurones

               Nota:

               • Sensory to motor
               1. Motor Neurones- short dendrites carry impulse from CNS to body. One long axon carries impulse from cell body to effector cells

                  Nota:

                  • CNS to effector
         3. Synapse= gap between neurones- information transmitted using transmitter chemicals
      2. Instructions (impulse) sent to effectors (muscles and glands)
         1. REFLEX- involuntary response
            1. Reflex arc bypass conscious CNS instead going through unconscious part of the brain or spinal cord
5. Endocrine System
   1. heart rate- affected by adrenaline
   2. hormones=chemical messages sent in the blood plasma activate target cells- slower than a nervous response but longer lasting effects
   3. Conc urine controlled by an anti-diuretic hormone (ADH) released by pituitary gland

      Nota:

      • Alcohol decreases ADH and Ecstacy increases ADH
6. Kidneys
   1. Remove Urea/ Adjust ions/ Adjust water content
      1. proteins can't be stored by body- amino acids converted into fats and carbohydrates in the liver. Urea= waste product and is poisonous. Filtered out by kidneys.
      2. wrong ion conc can disrupt osmosis- xs ions removed by kidneys- some also lost in sweat
      3. kidneys control how much water is excreted in urine
      4. Kidney Function
         1. 1-in a nephron- high pressure blood pumped into bowman's capsule. Blood vessels in BC act as a filter- Called Ultrafiltration
            1. 2- liquid flows along nephron useful substances reabsorbed - sufficient amounts of ion and water reabsorbed- ALL GLUCOSE reabsorbed
            2. 3- remaining substances released to bladder and leave the body as urine
7. DNA
   1. Double helix + nucleotides
   2. complementary base pairing
   3. Triplet code= amino acids produced
8. Inheritance
   1. Mitosis
      1. PMAT
         1. DNA duplication takes place in interphase not mitosis
   2. Meiosis
      1. produces gametes- 4 with different combinations of parent DNA
   3. Be able to draw genetic diagrams
      1. e.g cystic fibrosis caused by recessive allele
         1. Polydactyly dominant
         2. Huntington's Dominant
   4. Stem Cells
      1. undifferentiated cells
9. Homeostasis

   Nota:

   • Maintaining constant internal environment
   1. Negative Feedback

      Nota:

      • When the level of something is too high or too low the body uses negative feedback to bring it back to normal
   2. Temperature
      1. Hypothalamus (thermoregulatory centre) receptors sensitive to blood

         Nota:

         • also receives information from skin receptors
      2. Too Hot?- hairs lie flat/ sweat/ vasodilation
      3. Too Cold? Hairs stand on end/no sweat/ vasoconstriction/ shivering
   3. Blood Glucose
      1. controlled by pancreas
      2. Too High? Insulin released and glucose is removed by the liver