Foundations Of Medicine Flashcards
Define quaternary proteins
Fourth level of the structure, several polypeptides (subunits) interacting together to form a structure
Define a secondary protein
2nd level of structure, 3D spatial arrangement which relies on hydrogen bonding
What is a receptive field
Somatic sensory neuron activated by stimuli in a specific area
Explain the structure of a neuron
Cell body Dendrites (receive information) Initial segment - axon hillock (triggers action potential) Axon - (sends action potential) Axon - (release transmitter)
Why are barriers between fluid compartments important
Prevent too much secretion and absorption of waste and nutrients between compartments and maintain electrochemical gradient
Describe how an action potential works
Cell reaches threshold and then sudden massive depolarisation occurs, followed by repolarisation
What’s the structutre of skeletal muscle
Striated, multinucleate, bundles of fibres encased in connective tissue sheets
What is abnormally low levels of circulating plasma proteins called and what effect does it have
Hypoproteinaemia - oedema due to loss of on optic pressure
What is a non-competitive inhibitor
Binds to site other than active site, causing conformational change which prevents substrate from binding
What are the different types of glia and what are their functions
Astrocytes - maintains external environment of neurons, surround blood vessels & produce blood brain barrier
Oligodendrocytes - form myelin sheaths in the CNS
Microglia - phagocytosis hoovers mopping up infection
How are lipids transported around the body
Fatty acids - through the blood carried in lipoproteins
Triacyglycerols - hydrophobic so carried in lipoproteins which have hydrophobic core and hydrophilic surfaces
What are abnormal functions of glands
Over/under proliferation
Over/under secretion
Loss of cilia beat
Describe the epithelial components of the kidney
made from epithelial cells and organised into nephrons used for filtration of the blood and excretion of urine
What are leukocytes
White blood cells
Nucleated, large cells involved in defence against pathogens
Define the major carbohydrates in the body
The three main monsaccharides in humans are glucose, galactose and fructose
The three main disaccharides are maltose, lactose and sucrose
What are platelets
Membrane bound cell fragments, rarely nucleated and formation is governed by thrombopoietin. They adhere to damaged vessel walls and exposed connective tissue to mediate blood clotting.
Explain contraction and relaxation of smooth muscle
Smooth muscle contracts by an increase of calcium which activates the x-bridge cycle
Smooth muscle relaxes via the action of myosin light chain phosphatase
What is muscle fatigue
Repeated muscle stim causes fatigue, whch prevents muscles muscles using up vast amounts of ATP which would cause rigor. (Depends on fibre type, length of contraction and fitness of individual)
Describe the formation of urea
Urea is formed in the urea cycle
Excess glutamate is metabolised in the mitochondria of hepatocytes
Ammonia is re-captured via synthesis of carbamoyl phosphate
Nitrogen from carbamoyl phosphate enters the urea cycle
Urea is formed through a hydrolysis reaction of arginine
What is endocytosis
when the membrane forms a vesicle to take molecules in which eventually disintegrates on the inside surface of the membrane, releasing its contents
What is the autonomic nervous system
controls the things we do without thinking about them
Messages are sent from one nerve cell to another through a ganglion
Contracts and relaxes smooth muscle
Importance of maintaining homeostasis
Allows the body and its internal processes to function normally
What is pathogenesis
The way a disease develops
What is meant by an electrochemical gradient
The combined gradient of chemical and electrical which determines the direction of which ions will move. (charge and concentration)
What is erythopoiesis
Process for the formation of red blood cells
What is Vmax in terms of enzymes and kinetics
The maximum rate of reaction (although it increases to infinity)
What are the functions of blood
Clotting Defence Carriage of gas Thermoregulation Maintenance of ECF pH
What is a graded potential
Graded potentials decide whether or not an action potential is fired, by reaching a threshold which set the action potential off
How are interneurons used in the golgi-tendon organs?
Activation of inhibitory interneurons to the agonist muscle causes decrease in contraction strength. Activation of excitatory interneurons to antagonist muscles.
Describe the structure and function of smooth muscle?
Smooth muscle has no striations, is spindle shaped, has thick myosin and thin actin filaments and is arranged diagonally across
Smooth muscle is used in organs and functions autonomically. e.g. blood vessels, bladder, etc.
What is an allosteric enzyme
An enzyme which contains many sub-units with many active sites. One substrate binding to an active site on the enzyme causes conformational changes to the other active sites on other sub-units
What does blood consist of
Plasma
Platelets
White blood cells
Red blood cells
What is lateral inhibition in relation to nerves
Receptors at the edge of a stimulus are more strongly inhibited than those in the centre
Allows precise localisation of a stimulus
What is the function of glycolysis
Glycolysis is a complex series of biochemical reactions, not requiring oxygen which splits glucose, glycogen and other carbohydrates into pyruvic or lactic acid
Do alpha 1 receptors relax or contract smooth muscle?
Contract
What is meant by diffusion
Process by which a gas or solution spreads to fill all available volume in a container (high concentration to low)
What is a common clinical problem that can arise from the urea cycle?
OTC - raised blood ammonia levels in birth which is toxic (inherited)
Which receptors are able to adapt?
Mechanoreceptors
proprioreceptors
NOT nocireceptors as important to respond to pain
How are proteins catabolised?
Proteins are broken down in exercising muscle to amino acids and transferred to the liver where it can then be converted into ammonia and excreeted as Urea
What is the average amount of blood in the average male?
5 Litres
Explain the sliding filament theory of muscle contraction?
When muscle shortens from its relaxed state, the muscle fibres slide together and so the bands inbetween the muscle shorten and the length of the muscle decreases.
Describe the reflex mediated by Golgi tendon organs?
Inverse stretch reflex is caused by afferent nerves from the Golgi tendon organs firing more action potentials. This causes a decrease in contraction strength and so the muscle relaxes.
What is the structure and function of eicosanoids?
These are unsaturated fatty acids that are synthesised throughout the body.
They are signalling molecules which exert control over inflammation or immunity
Describe the anaerobic properties of muscle?
During anaerobic excercise; the diameter of muscle increases as well as glycolysis increases.
What is a competetive inhibitor?
Competitive inhibitors block the active site of an enzyme and decreases the affinity for the substrate for the enzyme. (Km increases)
Define globular proteins?
globular proteins are compact and have a round shape, e.g. haemoglobin
Define the function of steroid lipids?
Steroid hormones are chemical substances that act as chemical messengers in the body.
What is a nociceptor?
Responds to painful stimuli, tissue damage and heat
Characteristics which favour diffusion through the lipid bi-layer?
Small
Hydrophobic
Uncharged
Explain the affinity and effect of a full agonist, partial agonist and an antagonist?
Agonist - high affinity, full effect
Partial agonist - High affinity, partial effect
Antagonist - High affinity, No effect
What are proteoglycans?
Macromolecules found on the surface of cells or inbetween cells in the extracellular matrix. They form part of many connective tissues in the body.
What is an isosmotic solution?
An isosmotic solution has the same number of particles as regular ECF.
Explain the process of excitation-contraction in muscle?
The myosin cross-bridge use energy to generate the force of contraction and consist of heavy chains and actin and ATP binding sites.
What is exocytosis?
Exocytosis is when a vesicle filled with molecules travels to the ICF releasing its contents.
What is glycogen?
It is used to store glucose in human cells and is extensively more branched than starch and so can hold much more glucose.
Explain the synthesis of glycogen?
Glycogenin begins the process by covalently binding glucose from uracil-diphosphate to form a chain.
Glycogen synthase takes over and extends the chain.
Finally, the chain is broken by glycogen-branching enzyme and re-attached via bonds to give branch types.
Describe the synthesis of free fatty acids?
Fatty acid is synthesised from acetyl CoA which requires ATP and NADPH.
What is an excitory and inhibitory neurotransmitter?
An excitory neurotransmitter is when the cell depolarises and so is more likely to fire an action potential
An inhibitory neurotransmitter is when the cell hyperpolarises and so is less likely to fire an action potential.
What are the sources and effects of intracellular Ca2+ as a second messenger.
Sources;
internal stores in endoplasmic reticulum
voltage or ligand-gated channels
inhibition of Ca2+ transport out of the cell
Effects;
affects target protein
binds to calmodulin which then activates target protein
What are the main molecules in the body where nitrogen is found?
Amino acids and DNA
Descrbe negative feedback control?
Negative feedback control is the process of responding to homeosatic change from a signal (either nervous or endocrine) top return the body to its normal internal conditions.
Define Osmolarity?
Osmolarity defines the total number of particles in solution but not their nature (penetrating and non-penetrating).
Define fibrous proteins?
Fibrous proteins are made of long narrow strands, e.g. muscle fibres and connective tissue
What are erythrocytes?
Red blood cells
Highly flexible
non-nucleated
densely packed with haemoglobin
What is leukopoesis?
White blood cell formation controlled by a mix of cytokines
List the membrane proteins and describe their function?
Receptors - Penetrate the membrane and allow communication of extracellular signals.
Transporters;
Channel proteins - create a pore through the membrane for which molecules can flow through, usually water and ions.
Carrier proteins - Move larger molecules from ICF to ECF and only open to one at a time.
Enzymes - Catalyse chemical reactions on the cell membrane.
Structural proteins - Anchor the cell membrane to both the intracellular skeleton and extracellular matrix.
What are glycoproteins and why are they present in the cell?
They are proteins that have carbohydrates covalently atached.
This may occur so that proteins solubility is increased, to influence protein folding and conformation, protect it from degredation and act as communication between cells.
What is Feed Forward control?
This is when receptors can anticipate change in the body’s internal conditions and so activate the response earlier.
Where do the sympathetic and parasympathetic nerves stem from?
Sympathetic - middle of spinal cord
Parasympathetic - top and bottom of the spinal cord.
Define the term antagonist?
Blocks the normal response of the receptor.
Describe the processes of transmembrane signalling?
Receptors that act as ion channels
Receptors that functions as enzymes
Receptors that directly alters enzyme activity, but that enzyme is another protein
G-protein coupled receptors
What is myelination?
Allows the depolarisation at one node to spread as a local current so that the action potentials can be fired faster due to the current travelling further.
Explain the process of degredation of glycogen?
Glycogen monomers are removed one at a time from the non-reducing sugar ends.
Glycogen near the branch is removed by a de-branching enzyme.
Transferase activity removes a set of three glycogen residues.
Glycosidase activity then removes the final glycogen.
The unbranched chain can be further degraded.
How is glucose absorbed?
It is absorbed through an indirect ATP-powered process where an Na+ pump allows glucose to continually be moved into the epithelial cells.
What is an isotonic twitch?
An isotonic twitch is contraction with shortening length. e.g. running
What is aetiology?
The cause of disease
Which receptors does the sympathetic system act upon?
Nicotinic
Alpha or Beta
Explain the steps of the nueromuscular junction transmission?
- Motor neuron fires action potential
- Ca2+ enters through voltage-gated channels in presynaptic terminal
- Triggers fusion of vesicles
- Acetyl choline is released
- Diffuses across synaptic cleft
- Binds to acetylcholine receptors
- Na+ enters through open Na+ ligand-gated channels
- Evokes graded potential
- Depolarizes adjacent membrane to threshold
- Opens voltage-gated Na+ channels evoking a new action potential
- Acetylcholine is removed by acetylcholinesterase
How does concentration of an enzyme or substrate effect rate of reaction?
Increasing substrate concentration will increase the initial rate of reaction until all the active sites have been taken up.
Increasing enzyme concentration will increase the rate of reaction until all the substrates have been used up.
What does essential fatty acid mean?
Are essential in humans and deficiencies can lead to intestinal diseases, depression and ADHD.
What is adaption of a nerve?
Some mechanoreceptors adapt to a maintained stimulus and so will only signal change.
What two molecules are used to transport electrons?
NADP+ & NAD+
What is proteolytic cleavage?
Enzymes can exist as inactive precursor proteins. These can be cleaved to form active enzymes
What is diagnosis and prognosis.
Diagnosis - The identification of an illness or disease based on symptoms.
Prognosis - The likely result that the illness or disease will have (e.g. death)
How is NAD+ regenerated?
NADH is converted back to NAD+ at the final stage where pyruvate is converted into another molecule.
What is a glycosidic bond?
A type of covalent bond that links monosaccharide monomers together.
What is tetanus?
Tetanus is a sustained muscle contraction that is evoked when the motor neuron emits action potentials at a very high rate.
What is a proprioceptor?
Mechanorceptors in joints and muscles, signal information about body or limb position
Explain what an EPSP is?
An EPSP is when cells are depolarised by transmitters opening channels permeable to Na and K, but more Na travels in than K out and so it depolarises. (or by opening more leaky K+ channels)
Explain homeostasis in terms of water balance?
Any water lost must be replaced by water intake. Water lost ios controlled by the kidneys. Water intake is controlled by the thirst mechanism.
What are the functions of proteins?
Structural Enzymatic Receptor Hormonal Contractile Storage Transport
Describe the epithelial components of the liver
arranged in rows and cords and is responsible for secretion
What is the fate of dietry amino acids?
They are broken down and transported to the liver as alanine. This is then converted into pyruvate and then ammonia before being converted into urea for the urea cycle.
What is the function of muscle spindles?
They monitor muscle length and rate of change of muscle length
Control reflexes and voluntary movements
What is the michaelis constant?
The first part of the reaction occurs reversibly and is fast where as, the second part of the reaction is very slow
How can muscle contraction be controlled by motor units?
Motor neurons attach to several muscle fibres and so the contraction can be spread across the muscle. This allows the muscle to carry on working if one of the muscle neurons die
Describe the catabolism of fatty acids by beta-oxidation?
The beta-oxidation pathway degrades fatty acids two carbons at a time, which produces acetyl CoA and also NADH and FADH2.
Occurs in mitochondrial matrix.
Fatty acids are activates in the cytosol
Transport into the mitochondria
Degradation to two carbon fragments (acetyl CoA) in the mitochondrial matrix
Describe the stretch reflex?
A stretch reflex follows a sharp tap to an inelastic tendon. Force is transmitted to the muscle fibres as they are more elastic than tendons and so are more able to stretch
How can ketone bodies be an indicator of diabetes?
Diabetes leads to a high concentration of ketone bodies due to th inability of glucose to be broken down and so ketone bodies are broken down excessively as a substitute.
When the rate of ketone body production exceeds utilisation a fruity odour in breath due to acetone occurs.
What receptors does adrenaline and noradrenaline act on?
adrenergic receptors
Alpha receptors
Beta receptors
Explain what an IPSP is?
Cells are hyperpolarised by opening more Cl- or K+ channels which takes them away from the threshold and so is inhibitory
Define glucokinase and hexokinase and there contrast?
Glucokinase can phosphorylate all the glucose quickly and so most absorbed glucose is trapped in the liver
Hexokinase can grab glucose effectively at low [Glc] and are easily satisfied so don’t keep absorbing glucose
Glucokinase; High Km, High Vmax
hexokinsae; Low Km, Low Vmax
What are the 4 types of tissue and their function?
Connective tissue - connects tissues and liquid to a solid matrix.
Muscle tissue - Contractile long thin cells that allow movement
Nervous tissue - Allows communication by recieving, generating and transmitting electrical signals.
Epithelial tissue - covers surfaces (skin) and forms glands.
How is glutamate used in the transfer of nitrogen between amino acids?
Glutamate can donate ammonia to pyruvate to make alanine which can then transfer the nitrogen
How can reflexes be used to localise a problem in the spinal cord?
Reflexes evoked above but not below a level of the spinal cordxcan localise where the problem lies within the spinal cord.
How can enzymes be used in clinical diagnosis?
We can measure activity and compare to normal values to identify processes that are not functioning properly. Also enzymes in the wrong place tell us about disease.
Explain the flexor withdrawal reflex?
Flexor withdrawal reflex’s use information from pain receptors in skin, muscles and joints to withdraw that part of the body away from the painful stimulus and in towards the body. They do this by increasing sensory AP’s from pain receptors.
Describe the function and basic process of the citric acid cycle?
The citric acid cycle generates large amounts of energy through the electron transport chain.
Acetyl CoA (C2) to Citrate (C6) to Oxaloacetate (C4)
repeat
Why is the CNS more complex than the neuromuscular junction?
There is a range of neurotransmitters
There is a range of postsynaptic potentials
How do enzymes catalyse reactions?
The enzyme lowers the activation energy, allowing the reaction to proceed via a different route which is much quicker.
Define the dilution principle?
The measurements of body fluid compartments can only be measured using a substance that will remain in a specific compartment without transferring to another compartment.
Describe the aerobic properties of muscle?
During aerobic excercise; mitochondria, vascularisation and fibre diameter are all increased in the muscle.
Describe the term gland? (and endocrine and exocrine)
Collections of secretory epithelial cells and are either single celled or multicellular.
Exocrine glands secrete mucous rich in protein.
Endocrine glands are unable to store the secretion and so store fat molecules which secrete instead.
How are ketone bodies synthesised?
During fasting, glucose is decreased and excess acetyl CoA is converted to ketone bodies. They are formed in the liver and are transported with the blood to other cells to be used as fuel.
Define the structure of the neuromuscular junction?
Axon
Axon terminal
Synaptic cleft
Motor end plate
What is an epithelium?
The thin tissues forming the outer layer of the body’s surface as well as the lining or organs and blood vessels.
What does agonist mean?
Mimics the normal response of the receptor
What are the different uses for conncetive tissue?
- Blood/bone marrow
- Mucous
- Reticular
- Loose • Dense – regular/irregular
- Cartilage
- Bone
- Adipose (fat)
How is nitrogen transported through plasma to the liver?
Pyruvate and glutamate are converted into alanine and glutamine which are uncharged, soluble molecules that can cross the cell membrane.
Describe the basic structures of membranes?
Selective barrier (ions) Permeability can vary Thin bi-layer of lipids Flexible Insulators against electrical charge embedded with proteins
What does the golgi tendon organ do?
Monitors muscle tension and stretch of tendon.
Describe the basic functions of receptors?
Receptors respond to a specific chemical messenger and allow a cell to produce a response.
Receptors enable specificity, evoke an appropriate response and come in families built along similar lines.
What receptors does noradrenaline and adrenaline act on?
Adrenergic receptors
Alph and Beta receptors
How does stimulus intensity affect a nerve?
The larger the stimulus, the larger the receptor potential is, and so a higher frequency of action potentials are fired.
What is the efficacy of an agonist?
The efficacy is a measure of how much a receptor is activated.
Does beta2 receptors relax or contract muscles?
Relax
Can’t B2 relaxed
What is Km?
The substrate concentration when the reaction rate is at half of its max
Outline the process of lipid digestion and absorption?
Bile salts emulsify dietary fats in the small intestine
Intestinal lipases degrade triglycerol
Fatty acids and other breakdown products are absorbed by the intestinal mucosa and converted to triaglyceroids.
Triaglycerols are incorporated with cholesterol
Lipoprotein lipase converts triaglycerols into fatty acids
Fatty acids enter cells
Fatty acids are oxidized as fuel
Define the term affinity of a drug for a receptor?
Affinity is determined by the strength of the chemical reaction.
What are the properties of action potentials?
Have a threshold All or none Self propagating Have a refractory period Depolarising Voltage gated channels Many action potentials can be fired
What is a carrier mediated transport system?
The movement of molecules against their electrochemical gardient (active transport). They are only open to either the ICF or the ECF at one time and transport molecules between them.
What is used to control the autonomic nervous system?
Hypothalamus
What is an isotonic solution?
An isotonic solution has the same number of non-penetrating particles as regular ECF.
What is a mechanoreceptor?
A receptor stimulated by machanical stimuli.
What is colloid oncotic pressure?
When plasma proteins cannot cross the capillary walls and so the volume of plasma and interstitial fluid increases. The concentration remains unchanged, only the volume changes.
What are the properties of graded potentials?
Graded Can summate to reach threshold Decremental De or Hyper-polarising Ligand gated channels
Identify the major lipid classes and identify their role in disease?
Fatty acids - essential in human diet and used as a reserve energy source.
Triacylglycerol - The main dietry lipid which is digested in the small intestine.
Phospholipid - hydrolysed into fatty acids in order to be digested.
Glycolipid - to maintain the stability of the cell membrane
What are the three body fluid compartments?
Plasma, Interstitual fluid (ISF), Intracellular fluid (ICF)
Which receptors does the parasympathetic nerves act upon?
Muscarinic
Nicotonic
What is the function of ketone bodies?
They are used as a fuel source in the body. Cardiac and skeletal muscle both use as an energy source.
What is the lifespan of red blood cells?
120 days
Describe the function of cholesterol?
Cholesterol esters are digested to form cholesterolm and free fatty acids which can be used in energy production.
They are also the starting material for the synthesis of steroid hormones.
Outline the stages in the body where glucose is digested?
Mouth - saliva
Duodenum - pancreatic amylase
Jejunum - Final digestion, isomaltase, glucoamylase, sucrase and lactase
What does the parasympathetic nerves do?
Not so coordinated but controls rest and digest mechanisms.
What is the sympathetic and parasympathetic nervous system?
Sympathetic - fight or flight
Parasympathetic - rest and digest
How are electrons transported to Oxygen in the ETC?
electrons are transported by proteins (ubiquinone, ubiquinol and cytochrome C) which pumps hydrogen ions and then can be bonded to oxygen at the end of the chain.
What does the sympathetic nervous system do?
Controls the fight or flight mechanism
What is an isometric twitch vs. Isotonic
Isometric: muscle contraction where the length of the muscle doesn’t change (same length, changing tension: e.g. trying to bicep curl with bar stuck to floor(arm can’t lift but muscle still contracts)
Isotonic: muscle contraction where the length of the muscle changes (same tension, changing length: e.g. barbell curl, bicep muscle shortens)
Describe the ionic basis of the resting membrane potential?
All the potassium is moved into the cell and all the sodium is pushed out of the cell.
Pores are created in the membrane which are only permeable to potassium and so the potassium is pushed out through its concentration gradient until it equals the electrical gradient pushing it back in to the cell.
The equilibrium potential (electrochemical gradient)
Why can damaging muscle tissue have large consequences?
Damaged muscle tissue is replaced by scar tissue not muscle. Muscle will never fully recover.
Explain the citric acid cycle?
pyruvate is converted to Acetyl-CoA (2C)
Acetyl CoA combines with oxaloacetate to form Citrate (6C)
CO2 is released and NAD+ forms NADH
Citrate then reforms oxaloacetate (4C)
The electrons gained in NADH is then transferred to the electron transport chain.
What receptors does acetylcholine act on?
Cholinergic receptors
Nicotinic receptors
Muscarinic receptors
What are the different types of neurons?
Afferent (sensory) - PNS
Efferent (motor) - PNS
Interneurons - CNS
What receptors do acetyl choline act on?
cholinergic receptors
Nicotinic receptors
Muscarinic receptors
What are the extracellular matrix fibres?
The fibres are often made out of collagen and are often seen in tendons
Does beta 2 receptors relax or contract smooth muscle?
relax (can’t B2 relaxed)
Define a tertiary protein?
Third level of structure, when functional groups of R chains of amino acids interact with eachother.
Do these ions flow in or out of the cell? K+, Na+, Cl-, Ca2+
K+ OUT
Na+ IN
Cl- IN
Ca2+ IN
Define a primary protein?
The first level of structure, amino acid monomers joined together in a straight chain.
What is the fate of the carbon skeletons in catabolised protein?
Some feed into gluconeogenesis, producing glucose or glycogen in the liver.
Some feed into acetoacetate or acetyl CoA.
Explain the organisation of the nerves in the spinal cord?
31 Pairs + 12 cranial; 8 Cervical (neck, shoulder and arms) 12 Thoracic (Chest and abdomin) 5 Lumbar (Hips and Legs) 5 Sacral (genitalia and gastrointestinal tract) 1 Coccygeal
What are the irreversible steps in glycolysis?
- Phosphorylation of glucose.
- Phosphorylation of F-6-P to F-1,6-bisP (first committed step of glycolysis)
- Transfer of P from PEP to ADP.
What is the difference between a symptom and a sign?
Symptom: subjective - apparent only to the patient (e.g. back pain)
Sign: objective - evidence of a disease that can be observed (e.g. skin rash)
What is the natural history of a disease?
The progression of a disease process in an individual over time, in the absence of treatment
What is classification of a disease?
Several disease classifications:
- topographic - by bodily region or system
- anatomic - by organ or tissue
- physiological - by function or effect
- pathological - by the nature of the disease process
+ many more!
Define metabolism, catabolism and anabolism
Catabolism - breaking down of components for energy
Anabolism - building of compounds which requires energy
Metabolism - chemical processes involving both catabolism and anabolism in order to function
What is the role of the cytoskeleton
- Holds organelles in place and moves them
- Supports and maintains cell shaper
Define the term ‘hydrogen bond’
Electrostatic force of attraction between H atom covalently bound to a more electronegative atom, and another electronegative atom bearing lone pair of electrons
Define roles of eukaryotic animal cell organelles: nucleus, nucleolus, ER, ribosome, Golgi apparatus, lysosome, peroxisome, mitochondrion, flagellum, cilium
- Nucleus: control and regulate activities of cell (growth and metabolism), carries the genes
- Nucleolus: facilitating ribosome biogenesis
- ER: production of proteins (synthesis, folding, modification and transport of proteins)
- ribosome: protein synthesis in the cell (reads and translates mRNA into amino acid sequence)
- Golgi apparatus: process and package proteins and lipids (often to be exported out of cell)
- lysosome: membrane-bound organelle containing digestive enzymes
- peroxisome: catabolism of fatty acids (long chained and branched)
- Mitochondrion: generate chemical energy for the cell
- flagellum: locomotion (movement)
- cilium: move cells and material
Describe the structure and function of the plasma membrane
Structure: phospholipid belayer with embedded proteins that separate the internal contents of the cell from its surrounding environment
Function: control passage of organic molecules, ions, water and oxygen into and out of the cell (maintain electrochemical gradient)
Describe the interactions between water molecules and solutes that determine solubility
Water will only dissolve polar solids
Define the term pH
Scale used to specify acidity if basicity if aqueous solution. Measure of how many protons are in solution (more protons more acidic)
What is a buffer
Aqueous solution that can resist significant changes in pH levels.
A buffer is a mixture of a weak acid and its conjugate base
Explain the difference between osmolarity and tonicity
Tonicity only measures the [non-penetrating solutes] through a semipermeable membrane. Osmolarity measures the total [penetrating and non-penetrating solutes]
What’s the difference between an isosmotic solution and an isotonic solution
Isotonic refers to a solution having the same solute concentration as in a cell or body fluid.
Isosmotic refers to the situation of two solutions having the same osmotic pressure
Describe the fate of blood lactate
Blood lactate is transported to the liver where it is reconverted to glucose/glycogen by gluconeogenesis/glyconeogenesis
Describe the consequences of demyelinating diseases
Multiple sclerosis (MS) - can lead to vision loss, muscle weakness, muscle stiffness and spasms
Describe common excitatory and inhibitory neurotransmitters
Excitatory:
- glutamate (the most common neurotransmitter in the CNS)
Inhibitory:
- GABA (blocks certain brain signals and decreases activity in your nervous system)
Explain ipsilateral and contralateral reflexes
Reflexes categorised by the relative position of the sensory receptors to the responding muscle.
Ipsilateral: same side of the body
Contralateral: opposite side of the body
5 components of the reflex arc
Sensory receptor -> sensory neuron -> integration centre -> motor neuron -> effector target
Describe the composition of plasma
91% water
9% solids
Solids mainly comprise of coagulants (mainly fibrinogen - aids in clotting), plasma proteins (albumin - helps keep fluid in your bloodstream, globulins - immunoglobulins (immune response) and transport of ions, hormones and lipids)
What is oncotic pressure and factors responsible for generation
Form of osmotic pressure induced by the protein albumin. This pulls water into the circulatory system
Five types of white blood cells
Granulocytes: neutrophils, eosinophils, and basophils
Monocytes
Lymphocytes: T cells and B cells
Mnemonic: Never Let Monkeys Eat Bananas (also that neutrophils should always be present in higher amounts compared to other cell types)
What’s the difference between monocyte and macrophage
Monocytes:
- largest type of white blood cell
- play important role in the adaptive immunity process
- typically circulate in blood for 1-3 days before migrating into tissues Where they become macrophages
Macrophages:
- monocytes which have from bloodstream into tissues
- aid with phagocytosis
Factors controlling white blood cell formation
Stem cells in bone marrow responsible for producing white blood cells.
Bone marrow stores 80-90% of white blood cells, when infection or inflammatory condition occurs the body releases white blood cells to fight infection
What is meant by haematocrit
Haematocrit measures the proportion of red blood cells in blood
What is the normal value for haematocrit, how miss they change under certain circumstances
Normal haematocrit is between 41-50% in men, 36-44% in women.
May change due to: age, sex, anemia, kidney failure, pregnancy
What does blood viscosity mean
Viscosity: the resistance of fluids against flow. The resistance for blood circulation includes friction between blood elements and between the vessel lumen and blood.
Blood viscosity is a measure of the resistance of blood to flow. Can be described as thickness and stickiness of the blood
Why may blood viscosity change?
- Increased red cell mass
- increased red cell deformity
- increased plasma levels of fibrinogen and coagulation factors
- dehydration
Major cells involved in the innate and adaptive immune response system
Innate:
- macrophages
- neutrophils
- eosinophils
- basophils
- mast cells and dendritic cells
Adaptive:
- B cells (B lymphocytes)
- variety of T cells (T lymphocytes)
Describe the main role of the innate immune system
- first line of defence
- Main purpose is to immediately prevent the spread and movement of foreign pathogens throughout the body.
What are natural killer cells and what are their functions
- effector lymphocytes of the innate immune system
- function to limit the spread of tumours and microbial infections to prevent subsequent tissue damage
Describe the process of phagocytosis and intracellular killing
phagocytosis: process where cell binds to item it wants to engulf and draws it inwards engulfing it into a membrane bound vacuole called a phagosome.
Engulf object is then digested by hydrolytic enzymes contained in lysosomes
Define the primary and secondary lymphoid organs and their functions
Primary:
- red bone marrow and thymus (create lymphocytes)
Secondary
- lymph nodes, spleen, tonsils (filter out pathogens and maintain population of mature lymphocytes)
Role of b-lymphocytes in immunity
Provide defence against pathogens.
- make antibodies against antigens
- develop into memory cells after activation by antigen interaction
What is the antibody structure and function
Structure: An antibody (also known as immunoglobulin) is a Y-shaped structure consisting of 4 polypeptides. 2 heavy chains and 2 light chains.
Function: bind to foreign antigens and activate the complement system to destroy the cells by lysis (punching holes in the cell wall)
How do antigen processing cells (APCs) and T-lymphocytes interact
APCs interact with T cells to link innate and adaptive immune responses. APCs can directly influence the differentiation of T cells
Describe the complement system and its main function
The complement system helps the ability of antibodies and phagocytic cells to clear pathogens from an organism. Part of innate immune system
Describe the role of cytokines as chemical messengers within in the immune system
Important role during initial response to infection (acute inflammation). Cytokines attract and activate components of the immune system, promote blood clotting and facilitate the release of additional chemical messengers.
Immune cells use cytokines as chemical messengers to communicate. Cytokines released from one cell affect the actions of other cells
Describe the role of T-helper 1 and T helper 2 lymphocytes in controlling the immune response
- Important role in immunity
- Stimulate cellular immune response
- Both help stimulate B cells to proliferate and differentiate into either antibody-secreting effector cells or memory cells
