Just some stuff that can help

1. F214

2. Action Potential
1. Resting state- Polarised -60mV > outside
2. Sodium ion channels open & Na+ diffuse in
3. Membrane depolarises and becomes -50mV > outside
4. Voltage gated Na+ channels open, more ions enter, cell
becomes positively charged
5. P.D reaches +40mV
6. Sodium channels close & potassium channels open
7. Potassium ions diffuse out, P.D become –ve and cell
repolarises
8. P.D overshoots become hyperpolarised
9. Original P.D restored so cell returns to resting state.

3. Local Currents
Movements of ions along a neurone. Flow of
ions caused by increase in concentration at one
point, which causes diffusion where the ions
diffuse away from the region of higher
concentration.

4. Myelin Sheath
Insulating layer of fatty materials made from
Schwann cells. Gaps between called nodes of
Ranvier, these cause the local currents to
elongate so Na+ diffuse from one to the next.
This means the action potential appears to jump
from one node to another. Saltatory conduction.
Advantages of this are that action potentials can
only occur at nodes or Ranvier speeding up
transmission of action potential.

5. Nerve Junctions
Synaptic Knob has:
• Many mitochondria indicating processing
needing ATP occurs
• Large amoung of smooth ER
• Vesicles of acetylcholine
• Voltage-gated calcium ion channels

6. Transmission across synapse
• Action potential arrives at knob.
• Voltage gated Ca+ channels open and Ca+ diffuses in
• Ca+ causes synaptic vesicles to move and fuse with
presynaptic membrane
• Acetylcholine is released by exocytosis & diffuse across cleft
• Acetylcholine bind to receptor sites on Na+ channels in
postsynaptic membrane & Na+ channels open
• Na+ diffuse across postS membrane into the postS neurone
• Generator potential is created if this combined reaches
sufficient levels then threshold potential is achieved
• A new action potential is been created in the PostS neurone

7. Acetylcholinesterase
Enzyme found in synaptic cleft. It hydrolyses
acetylcholine to ethanoic acid and choline. This
stops transmissions so action potentials aren’t
continued.

8. Endocrine System
Endocrine Gland- secretes hormones directly into the blood, has
no ducts.
Exocrine Gland- secretes molecules into a duct that carries
molecules to where they’re needed.
Adrenaline
• Can’t enter cell therfore it binds to the first complementary
receptor site.
• Adrenaline activates the enzyme Adenyl Cyclase
• Adenyl Cyclase converts ATP to cAMP which then activates
enzymes within the cell.

9. Regulation of Blood Glucose
Pancreatic Duct- tube that collects all secretions from the exocrine cells in the
pancreas and carries the fluid to the small intestine.
Alpha Cells- Secrete hormone Glucagon
Beta Cells- Secrete hormone Insulin
Glycogen > Glucose (Glycogenolysis)
Glucose > Glycogen
Type 1 Diabetes- insulin dependent, starts in childhood usually
Type 2 Diabetes- Non-insulin dependent

10. Excretion
Excretion- The removal of metabolic waste from
the body.
Carbonic Acid Dissociation:
H₂0₃ → H⁺ + HCO ₃⁻
Deamination:
Amino Acid + Oxygen → Keto Acid + Ammonia
Formation Of Urea:
2NH₃ + CO₂ → CO(NH ₂) ₂ + H₂O

11. The Liver
Blood from Aorta → Hepatic Artery → Liver
De-ox Blood from Hepatic Portal Vein → Liver
Blood leaves via Hepatic Vein
Bile Duct secretes bile from Liver → Gall Bladder

12. Kupffer Cells
Are specialised macrophages, they move in
sinusoids and breakdown/recycle. Bilirubin is a
breakdown of the RBC and is excreted as part of
bile. Bilirubin causes the brown pigment in
faeces.

13. Ornithine Cycle
Ammonia+ Carbon Dioxide → Urea +Water

14. Detoxification
Detoxyfication of Alcohol
Ethanol→Ethanal → Ethanoic Acid →Acetyl CoA (Goes To Respiration)
2H removed from Ethanal & Ethanoic Acid by NAD
NAD + 2H → Reduced NAD

15. The Kidney

16. Kidney Fluid Composition
PCT- fluid altered by reabsorption of all sugars, salts
and some water. 85% of fluid reabsorbed here.
D LoH- Ѱ decreased by addition of salts & removal of
water
A LoH- Ѱ increased as salts removed by active transport
CD- Ѱ decreased by removal of water, ensures urine has
low Ѱ . Meaning urine has higher conc. of solutes than
in blood and tissue fluid.

17. Ultrafiltration
Blood flows into glomerulus form afferent arteriole.
This is wider the efferent arteriole. This difference ensures pressure is higher
in glomerulus than the Bowman’s capsule, pushing fluid from the blood into
Bowman’s capsule. Basement membrane stops bloods cells and proteins
passing through. Podocytes allow fluid to travel between them into Bowman’s
capsule.
Filtered Out of Blood
Water
Amino Acids
Glucose
Urea
Inorganic Ions (salts)

18. Selective Reabsorption
Structure/Anatomy
Cell surface membrane highly folder Greater SA
Co-transporter proteins – facilitated diffusion
Has mitochondria- ATP for active transport
Membrane of cell by blood supply has Na-K
pumps that pump Na out of cell and K in.

19. Selective Reabsorption
Sodium ions actively transported out of cell into tissue
fluid via sodium/potassium pumps.
Glucose or amino acids enter cells with Na+ by
facilitated diffusion involving co-transporter proteins.
Glucose and amino acids diffuse into blood capillary.
Low water potential in cells due to reabsorption of
salts/glucose means water enters cells and then blood
by osmosis.

20. Water Reabsorption
D LoH- H₂O out Na+ & Cl- in
A LoH- Na+ & Cl- out lower part
Active removal of ion out higher part
C D- H₂O out by osmosis & enters capillaries
Urine passes down collective duct to pelvis.

21. Osmoregulation
Collecting duct walls respond to ADH, increasing/ decreasing permeability.
Vesicles with aquaporins embed in membrane to change permeability.
Water potential of blood monitored by osmoreceptors in the hypothalamus.
When water potential in blood is low, cells shrink, stimulating neurosecretory
cells. These release ADH, which is in the hypothalamus which flows down the
axon to the posterior pituitary gland and stays until needed.
When Neurosecretory cells are stimulated it goes into blood capillaries
around the PPG and Is transported to the collecting duct.
Once potential of blood rises less ADH is released.
More ADH= More permeability
Less ADH= Less permeability

22. Dialysis
Dialysis- use of a partially permeable membrane to
filter blood.
Dialysis fluid matches blood composition.
Heamodialysis- blood taken from vein cleaned, herapin
added to reduce clotting, and bubbles removed.

23. Pregnancy Testing
Hormone hCG released when pregnant.
Pregnancy tests have monoclonal antibodies
which is specific and will only bind to hCG. hCG
binds and moves until it stiks to immobolised
antibodies. As a result antibodies have blue
bead and form a blue line. One blue line is a
control. The second line confirms pregnancy.