BMAT biology

BMAT biology

1. Digestive System

   • carbohydrates- salivary amylase to disaccharides and then monosaccharides
   • Proteins- pepsin, trypsin, chymotrypsin are proteases. In stomach
   • Fats- (emulsified by bile salts) + lipase
   • digestive tract is lubricated with mucus to protect from digestive enzymes

2. Respiratory System

   • Air Pathway
     • Nose-nasal cavity-pharynx-larynx-trachea-bronchi-bronchioles-alveoli
   • Mechanics of pulmonary ventilation
   • External Respiration- exchange of oxygen and carbon dioxide in the lungs- know what factors make lungs good site for gas exchange
   • During exercise glycogen is used. glucose from food is stored as glycogen in the liver and muscle cells
   • Artificial ventilators

3. Circulatory System

   • RBC adaption
   • Atrial systole/ ventricular systole, diastole
   • Comparison of blood vessels
     • arteries
     • Veins
     • Capillaries
   • clot= mesh of fibrin fibres
     • reaction- platelets exposed to damaged vessel
   • blood transfusions- RBC either have A or B antigens (or neither or both)
     • Plasma can contain anti A or anti B antibodies
     • if an A antigen meets an anti A antibodies causes agglutination (v bad)
     • blood group is important
   • Electrical control of heartbeat
     • 1SAN
     • 2AVN
     • 3Bundle of His/ Purkinje fibres

4. Nervous System

   • Sense Organs detect Stimuli
     • Contain receptors- change stimulus energy into electrical impulse
   • CNS coordinates response
     • brain and spinal cord
     • Neurons transmit information to and from CNS
       • Impulse passed along axon- cytoplasm fibre surrounded by cell membrane
         • some axons surrounded by fatty sheath to insulate
         • dendrites connect to other neurones
       • Sensory- long dendrite impulse from receptor to cell body- short axon carries impulse from cell body to CNS
         • receptor to CNS
         • Relay- Lots of short dendrites carry impulse from sensory n. to cell body, many short axons carry impulses from cell body to motor neurones
           • Sensory to motor
           • Motor Neurones- short dendrites carry impulse from CNS to body. One long axon carries impulse from cell body to effector cells
             • CNS to effector
       • Synapse= gap between neurones- information transmitted using transmitter chemicals
     • Instructions (impulse) sent to effectors (muscles and glands)
       • REFLEX- involuntary response
         • Reflex arc bypass conscious CNS instead going through unconscious part of the brain or spinal cord

5. Endocrine System

   • heart rate- affected by adrenaline
   • hormones=chemical messages sent in the blood plasma activate target cells- slower than a nervous response but longer lasting effects
   • Conc urine controlled by an anti-diuretic hormone (ADH) released by pituitary gland
     • Alcohol decreases ADH and Ecstacy increases ADH

6. Kidneys

   • Remove Urea/ Adjust ions/ Adjust water content
     • 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.
     • wrong ion conc can disrupt osmosis- xs ions removed by kidneys- some also lost in sweat
     • kidneys control how much water is excreted in urine
     • Kidney Function
       • 1-in a nephron- high pressure blood pumped into bowman's capsule. Blood vessels in BC act as a filter- Called Ultrafiltration
         • 2- liquid flows along nephron useful substances reabsorbed - sufficient amounts of ion and water reabsorbed- ALL GLUCOSE reabsorbed
         • 3- remaining substances released to bladder and leave the body as urine

7. DNA

   • Double helix + nucleotides
   • complementary base pairing
   • Triplet code= amino acids produced

8. Inheritance

   • Mitosis
     • PMAT
       • DNA duplication takes place in interphase not mitosis
   • Meiosis
     • produces gametes- 4 with different combinations of parent DNA
   • Be able to draw genetic diagrams
     • e.g cystic fibrosis caused by recessive allele
       • Polydactyly dominant
       • Huntington's Dominant
   • Stem Cells
     • undifferentiated cells

9. Homeostasis

   • Maintaining constant internal environment
   • Negative Feedback
     • When the level of something is too high or too low the body uses negative feedback to bring it back to normal
   • Temperature
     • Hypothalamus (thermoregulatory centre) receptors sensitive to blood
       • also receives information from skin receptors
     • Too Hot?- hairs lie flat/ sweat/ vasodilation
     • Too Cold? Hairs stand on end/no sweat/ vasoconstriction/ shivering
   • Blood Glucose
     • controlled by pancreas
     • Too High? Insulin released and glucose is removed by the liver