Exam must knows! Flashcards
2 eg. of functional cells and their functions
- Nerve cells- brain, direct cell communication, release chemical messages directly on to other cells.
- Germ cells- ova/spermatozoo, reproduction, haploid
Homeostasis
the tendency of a living organism to keep its internal environment relatively stable despite changes in the external environment
universal recipient
AB
universal donor
O
GI
2 changes in pregnancy due to progesterone
- Relaxation of lower esophageal sphincter-> heartburn
- Enlarging uterus compresses large intestine
- > flatulence
Peristalsis vs segmentation
- Segmentation occurs in small intestine, peristalsis occurs all the way from oesophagus to large intestine.
- In peristalsis, adjacent segments contract/relax, creating wave of movement.
- In segmentation, non-adjacent segments contract/relax, causing back & forth of food.
Hyperemesis gravidarum
intractable and persistent nausea & vomiting
Why avoid lambing/cat faeces?
Risk of Toxoplasmosis caused by toxoplasma gondii.
Can cause congenital learning difficulties, blindness
Why avoid soft cheese?
Listeriosis caused by bacterium listeria monocytogenes.
Can cause miscarriage, stillbirth
How to take Ferrous Sulphate
With orange juice- vit c enhances absorption of non-haem iron.
Avoid taking with tea as tannin will stop absoprtion.
Inform if any side effects.
Dietary fibre
Indigestible non-starch polysaccharides.
Found in cereal grains, veg, seeds (large amounts)
Fruit & veg (smaller amounts)
What is negative feedback?
Give eg.
A homeostatic process that changes the direction of the stimulus. May increase or decrease stimulus but stimulus is not allowed to continue as it did before.
eg. Regulation of blood sugar levels
2 functions of endocrine system
- Coordinates homeostatic balance
2. Modifies and induces behavioural changes within the individual.
2 hormones from hypothalamus, released by posterior pituitary gland
- Oxytocin
2. ADH- antidiuretic hormone
3 endocrine glands & functions
- Thyroid- metabolism & growth
- Thymus- immune system
- Gonads- sex steroids that affect reproductive cycles & gamete formation
What is a hormone?
Chemical substance secreted by cells that regulate metabolic function of other cells
regulation of HIGH blood sugar levels
Insulin is increased.
It stimulates sugar uptake by cells and glycogen formation in liver which decreases blood sugar. (Hypoglycaemic)
regulation of LOW blood sugar levels
Glucagon is increased.
It stimulates glycogen breakdown and increases blood sugar. (Hyperglycaemic)
What are neurons?
specialised nerve cells that transmit chemical and electrical signals.
2 parts of nervous system
- Peripheral
2. Central
Glial cells
Provide nourishment & support of neurons
2 types of synapse reactions
- Chemical- a neurotransmitter is released from one cell into another
- Electrical- electrical charge of one cell is influenced by the charge in an adjacent cell
Dendrite
Projections of a neuron that receive signals from other neurons
Epidural space
filled with adipose tissue and dense blood vessel network.
Located between dura mater and surrounding bone of vertebrae.
Synapse
gap between the presynaptic cell and the postsynaptic cell where information is traded (nerve impulse)
2 pregnancy changes to Nervous system
- Grey matter shrinks
2. Pituitary gland enlarges
Function of sensory neurons
convert external stimuli from the environment into corresponding internal stimuli
Function of motor neurons
project their axons outside of the CNS to directly or indirectly control muscles
Function of interneurons
relays nerve impulses between the sensory and motor neurons
2 somatic senses
- Thermoreceptors- temperature changes
2. Photoreceptors- light energy
1st line of defence
skin, mucosa
NK cells
2nd line of defence Type of lymphocyte Found in blood and lymph Release cytotoxic enzymes which degrade target cell contents. Target cell undergoes apoptosis.
4 signs of inflammation
- Pain
- Swelling
- Heat
- Redness
Active vs Passive immunity
Active Natural- bacterial/viral infections
Passive Natural- antibodies passed from mother to fetus through placenta/breast milk
Active artificial- vaccine with attenuated pathogens
Passive artificial- injection of gamma globulins for prophylaxis
4 steps of Rhesus incompatibility
- RH+ father
- Rh- mother carrying Rh+ fetus. Rh antigens from fetus circulate in Mother’s blood.
- In response to antigens, Mother produces anti-Rh antibodies.
- If woman becomes pregnant again with a Rh+ fetus, her anti-Rh antibodies will cross placenta and damage fetal red blood cells.
2 types of vaccine & eg
Inactivated- killed microorganisms, may need 2-3 injections eg. tetanus
Live attenuated- full, long lasting response after 1-2 doses eg. MMR
Homologous chromosomes
Pair of chromosomes with same genes but different alleles
Purpose of Meiosis I is to….
separate homologous pairs
Purpose of Meiosis II is to….
separate sister chromatids
eg of numerical chromosome disorder
Downs syndrome