GEM 1 Flashcards
Name the three most common anatomical planes and their divisions
Sagittal = left and right
Transverse or axial = superior and inferior
Coronal = posterior and anterior
Name the four basic types of tissue and give examples?
Connective tissue (bone, blood, adipose, cartilage, reticular)
Epithelial tissue (squamous, columnar, cuboidal)
Muscle tissue (skeletal, smooth, cardiac)
Nervous tissue (neurons, glial)
Name the 8 cranial bones
Name the systolic followed by diastolic reference ranges (mmHg) for: hypotension, normal, hypertension
<90/60 (hypotensive)
<120/80 (normal range)
>140/90 (hypertensive)
Name two functions of the blood in relation to thermoregulation
Distributing heat from active organs
Vasodilation or vasoconstriction to regulate blood flow towards the skin (convection)
Name five transport functions of the circulatory system
(Hormones) from endocrine glands to target tissues
Molecules and cells for the (immune system)
(Nutrients) from the digestive tract to the liver
(Oxygen) from the respiratory system to the cells
(Waste products) from our cells to the respiratory and excretory systems
What are the two hormones secreted by alpha and beta cells in the pancreas and what do they do?
Alpha cells secrete glucagon which stimulates the liver to release glucose into the blood and stops the liver from taking up more glucose.
Beta cells secrete insulin which stimulates the liver, skeletal muscle, and adipose tissue to take up glucose.
How much glucose (g) circulates in the blood of an average (70kg) adult at a given time?
4g
What are the three dietary monosaccharides?
Glucose, fructose, galactose
What are the three different types of capillaries and give some examples of where they can they be found?
Continuous - allow small molecules through (found in muscle, skin, fat, and nerve tissue)
Fenestrated - found where extensive molecular exchange occurs (small intestine, kidneys, endocrine glands)
Sinusoidal - contains larger gaps and an incomplete basement membrane for exchange of larger molecules and even cells (liver, spleen, lymph nodes)
Describe the ultrastructure of the arteries
Lumen - typically narrower in arteries compared to veins and without valves
Tunica intima - endothelium made up of simple squamous epithelial cells, followed by a basement membrane and internal elastic lamina
Tunica media - typically the thickest layer, made up of smooth muscle cells that can vasoconstrict or dilate, followed by the external elastic lamina
Tunica adventitia - consists of elastic and connective tissue as well as vasa and nervi vasorum
Describe the path of blood through the systemic circulation, starting from the pulmonary veins and ending with the capillaries
- Left atrium
- Mitral valve
- Left ventricle
- Aortic (Semilunar) valve
- Aorta
- Arteries
- Arterioles
- Metarterioles
- Capillary bed
What is pulse pressure and what is the normal range?
Difference between systolic and diastolic blood pressure
40-60mmHg
What is peripheral (vascular) resistance and where is it highest?
The resistance that must be overcome to circulate blood
Highest in arterioles (narrow lumen)
What are the four main components of blood?
55% plasma (water, proteins, ions, dissolved gases)
45% Erythrocytes
Leucocytes
Thrombocytes
What are the 3 main plasma proteins?
Albumin - Maintains oncotic pressure, carries molecules and drugs, scavenges free radicals
Fibrinogen - clotting factor
Globulins - Alpha (such as HDL), beta (such as LDL), gamma (Antibodies)
If fibrinogen and other clotting factors are removed from plasma, what is left?
Serum
What are 4 main steps of haemostasis?
Vasospasm - smooth muscle tissue contracts to reduce bloodflow
Platelet plug - collagen and von Willebrand factor in the vessel wall are exposed to thrombocytes, which activate and become dendritic. Thrombocytes also release Ca2+ which signals thrombocyte aggregation
Coagulation - fibrinogen is then converted to fibrin, which forms a mesh that traps more platelets and erythrocytes to form a thrombus
Fibrinolysis - plasmin breaks down the clot and anticoagulants and vasodilators are released
What are the four pillars of medical ethics?
Autonomy (of patient’s)
Beneficence
Non-maleficence
Justice
What is a solvent and give an example?
The liquid in which a solute is dissolved in to make a solution.
E.g. water is a solvent for salt (solute) which makes brine (solution)
How many particles does one mole (mol) contain?
6.02 x 10^23
Known as Avogadro’s constant
What is the relative charge and relative mass of the three subatomic particles?
Electrons: 1/2000 mass, -1 charge
Protons: 1 mass, +1 charge
Neutrons: 1 mass, 0 charge
What are the 3 dietary disaccharides?
Sucrose, Lactose, Maltose
Define cations and anions?
Positively (cation) or negatively (anion) charged atoms
What is an isotope?
A different form of an element that contains the same number of protons and electrons but a different number of neutrons
Which three factors affect Ionisation energy?
- Nuclear charge (number of protons)
- Distance from the nucleus (reduces with distance)
- Shielding (number of electrons between an outer electron and the nucleus)
Why does it take more energy to remove each successive electron from an atom?
Electrons are being removed from an increasingly positive ion so the force of attraction due to be broken is greater.
Why is it easier to remove an electron from an orbital containing two electrons?
Electron repulsion (as electrons are both negatively charged)
What happens to ionisation energy when moving down groups in the periodic table?
Ionisation energy reduces.
Each element down a group has an extra electron shell, (increased distance and electron shielding from inner shells)
What happens to ionisation energy when moving across periods in the periodic table?
Ionisation energy increases.
Increased number of protons (nuclear attraction) but at roughly the same level (no electron shielding)
What are valence electrons?
An electron in the outer shell of an atom which can participate in the formation of chemical bonds (e.g. covalent bonds)
Describe the structure of a neuron
Are epithelial tissues vascularised?
No. Epithelial tissues are avascular
What are the two main types of nerve cells?
Neurons and glial cells
Where is the pyloric sphincter and what does it do?
At the inferior end of the stomach. Allows chyme to pass into the duodenum.
What are the three phases of digestion?
Cephalic
Gastric
Intestinal
What are the 3 main roles of the liver?
Detoxification - the liver filters all blood from the stomach and intestines and metabolises drugs and toxins into less harmful/more usable components
Synthesis - of bile which is used for fat digestion, neutralising chyme, and for moving waste along the intestine
Storage - of fat soluble vitamins (A,D,E,K) and glycogen
What is the function of the gallbladder?
To concentrate and store bile which is synthesised in the liver
What is the role of the pancreas?
Produces digestive enzymes which are secreted into the duodenum (lipase, protease, amylase)
Produces pancreatic hormones (glucagon, insulin)
Where are leptin and ghrelin produced?
Leptin is produced in adipose tissue and inhibits hunger. Leptin production is directly proportional to the amount of adipose tissue one has.
Ghrelin is produced in the stomach. Ghrelin levels are highest before a meal
What are the two forms of endocytosis?
Phagocytosis - ingestion of particles
Pinocytosis - ingestion of liquid droplets
What is erythropoietin?
A hormone made in the kidneys that stimulates erythropoiesis (erythrocyte production).
What are the roles of the kidneys?
- Removal of wastes
- Control of blood pressure
- Control of blood pH
- Erythropoietin production
What could high levels of erythropoietin indicate?
Anaemia
How long is the average lifespan of an erythrocyte?
100-120 days
What is HbA1c and why is it unreliable in patients with sickle cell disease?
HbA1c measures glycated haemoglobin in the bloodstream and indicates average levels over the past 3 months (limited by erythrocyte lifespan of 100-120 days).
HbA1c is underestimated in sickle cell disease as erythrocyte lifespan is only 10-20 days.
Describe the structure of haemoglobin
2 alpha and 2 beta globins surround 4 heme groups. Heme group contains a porphyrin ring and one iron atom per group.
What is the mesentary and what is it’s function?
A fold of membrane that attaches the intestine to the abdominal wall.
Prevents intestines from collapsing or twisting.
What is the role of the smooth endoplasmic reticulum?
Synthesises and stores lipids (such as cholesterol and phospholipids).
Has various other functions.
What is the defining feature and what is the role of the rough endoplasmic reticulum?
Is studded with ribosomes.
Synthesises proteins
What is the function of the Golgi apparatus?
Responsible for modifying and packaging proteins and lipids into vesicles for exocytosis or transport around the cell
What is a lysosome?
Membrane bound organelles that contain digestive enzymes for invading pathogens or worn out cell parts
Give an overview of haematopoiesis and the two main lineages
Where are mast cells found and what is their role?
Located in connective tissue close to the external environment (mucosal surfaces, skin, intestines etc.)
Contains granules with histamine, heparin, cytokines and other inflammatory mediators. Involved with allergic reactions and parasitic defence
What is saltatory conduction?
Occurs in myelinated axons where an action potential in a node of ranvier triggers the flow of current to the next node, speeding up the transfer of nerve signals
What is the difference between the autonomic and somatic nervous system?
Autonomic - mediates unconscious activities. Only has motor pathways
Somatic - mediates conscious activities. Has motor and sensory pathways
What does a natural killer cell do?
Innate immune cells that destroy damaged cells which no longer produce major histocompatability complex 1 (mhc1) on their cell surface
What is haematocrit and what are the normal ranges in men and women?
% of erythrocytes in the blood.
Men: 41-50%
Women: 36-48%
What is the glycocalyx?
The sugar coat on the outer surface of the plasma membrane.
It aids in the binding of some cells and facilitates cell recognition.
What would happen if an erythrocyte was placed in a Hypertonic solution?
The fluid bathing the erythrocyte contains a high level of solute relative to the cytoplasm, therefore water would diffuse out of the cell, causing the cell to shrivel (Crenation).
Name two carrier-mediated transport systems and provide examples?
Facilitated Diffusion - Ion channels transported down an electrochemical gradient.
Active transport - Uses ATP to transport solutes against their concentration gradiets e.g. Na+, K+ pump
What is a gene?
A sequence of DNA that codes for a protein or polypeptide
How many homologous pairs of chromosomes do humans inherit?
23 pairs
What is the genotype?
The set of genes possessed by a particular organism
What is the phenotype?
The expression of the genotype - may also have environmental influences!
What are Newtons 3 laws of motion?
- A body will remain in a uniform state of motion unless acted upon by an external force
- F = ma
- For every action, there is an equal and opposite reaction
What is the starling principle?
Fluid movements between blood and tissues are determined by differences in hydrostatic and oncotic pressures between plasma inside microvessels and fluid outside them
What is the difference between laminar and turbulent flow and when do they occur?
Laminar flow is constant and often occurs at low velocities. Turbulent flow involves irregular fluctuations and mixing, often at higher velocities.
E.g. A waterfall exhibits both from start (laminar) to finish (turbulent) as water accelerates due to gravity.
In chemistry compounds ending in ‘ide’ are types of what?
Anions (negatively charged ions)
(e.g. chloride, oxide, sulphide)
What is a covalent bond?
A chemical bond that involves the sharing of electron pairs between atoms.
What is an ionic bond?
A type of chemical bond that involves the electrostatic attraction between oppositely charged ions, or between two atoms with sharply different electronegativities.
Ionic bones tend to be stronger than covalent bonds
Is a water molecule polar or nonpolar, and what is the net charge of a water molecule?
Water is a polar molecule as the oxygen atom hogs electrons, giving it a partial negative charge, whereas the hydrogen atoms have a partial positive charge.
The net charge of water is zero
Why is water both cohesive (sticks together) and adhesive (sticks to other things)?
Due to its polarity
Outline the main divisions of the human nervous system and their roles
What are the two human gametes?
Sperm cell - male
Egg cell - female
Are gametes diploid or haploid?
Haploid (23 chromosomes)
All other human cells are diploid, containing 23 chromosome pairs
What are the four main types of macromolecules?
Carbohydrates
Lipids
Proteins
Nucleic Acids
What are the four bases of DNA?
A - adenine
T - thymine
G - guanine
C - cytosine
What are the four RNA bases?
A - adenine
U - uracil
C - cytosine
G - guanine
What are the four protein structure types?
Describe the basic structure of an amino acid
Central Carbon atom
- Hydrogen
- Carboxyl group
- Amino group
- R side chain
List the four main types of carbohydrates and give examples for each
What are the three main types of lipids?
Phospholipids - used to make the polar bilayer of human cells
Sterols - Cholesterol is the primary sterol in humans. Formed in the liver and used to make hormones and bile salts. Phytosterols are found in plants.
Triglycerides - Found in food, the blood, and adipocytes. Either unsaturated or saturated
Describe the chemical structure of a phospholipid
Describe the chemical structure of a triglyceride
Glycerol backbone bound to 3 fatty acid chains
What are the three types of polysaccharides and their functions?
Starch - (amylose and amylopectin) plant energy storage
Glycogen - animal medium-term energy storage
Cellulose - plant structure (indigestible)
What is an enzyme?
Proteins that help to speed up chemical reactions in animals.
Enzymes convert ‘substrates’ into ‘products’ at the active site
Human enzymes normally work best at 37c and at a specific pH related to their area of operation.
Where are the adrenal glands located?
On top of the kidneys
‘Add’ - ‘Renal’
Describe how DNA is stored
As tangled chromatin fibres during interphase. Chromatin forms into chromosomes during Prophase.
Chromosomes are made from tight strands of chromatin. Chromatin is made of tight bundles of histones. DNA is wound around histones to form nucleosomes
Describe osmolarity
Osmolarity is the measure of solute concentration in a liquid.
Measured as Osmoles per litre (Osm/L)
What section of the nervous system does a reflex arc fall under?
Somatic nervous system
Why is iodine important for the thyroid?
Iodine is used to create thyroid hormones, namely triiodothyronine (t3) and thyroxine (t4).
Iodine deficiency slows the metabolism and eventually caused an enlarged thyroid (goiter)
Which part of the body regulates homeostasis?
Hypothalamus (via autonomic nervous and endocrine systems)
Which three pathways do the hypothalamus and pituitary gland use to direct neuroendocrine function?
HPT axis (homeostasis)
HPA axis (flight or fight)
HPG axis (reproduction)
What is cardiac output?
The amount of blood the heart pumps in 1 minute
= stroke volume (ml/beat) x BPM
What is a normal cardiac output for an average sized human at rest?
5-6 litres (per minute)
What is stroke volume and what is a normal range?
Volume of blood ejected out of the left ventricle at each heart beat.
50-100ml
Explain a reduction-oxidation (Redox) reaction
‘OIL RIG’
Oxidation is loss of electrons (becomes positively charged)
Reduction is gain of electrons (becomes negatively charged)
What is an electronegative element? Give an example
An element which attracts electrons (to fill a shell).
Fluorine is the most electronegative element (1 electron away from filling its shell)
What is the ratio of the sodium-potassium pump found in a neuron?
3:2
3 Na+ pumped out for every 2 K+ brought in