Biomed Flashcards by Grace Cooper

List the different phases of mitosis starting with G0

G0, Interphase (G1, S, G2), mitotic phase (prophase, metaphase, anaphase, telophase), cytokinesis

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What are the 3 types of stem cells and what order do they go in? (plus a bit of info about stages of fetal development)

Totipotent (from zygote to merulla)

Pluripotent (from blastocyst [after merulla] to epiblast and hypoblast [placenta])

Multipotent (adult stem cells)

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What is the difference between embryo and fetus?

Embryo is 2-8 weeks and fetus is after 8 weeks

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Gastrulation: What are the 3 primary germ layers and what arises from each?

Endoderm: gastrointestinal and pulmonary systems

Mesoderm: muscles (including heart), skeletal system and genitourinary system

Ectoderm: skin (sweat glands/ hair) and nervous system

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What is recombination and when does it occur?

What is chiasma?

What is tetrad?

Recombination= crossing over (occurs between a pair of homologous chromosomes –> results in chromosomes with different combinations of alleles) It occurs in prophase 1

Chiasma= site of crossing over during synapsis

Tetrad= 2 homologous chromosomes joined at the chiasma (formed by synapsis)

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What is a carbohydrate?

What are the different types of carbs?

Molecule containing CHO

Monosaccharides= single sugar unit (6 carbons) [glucose, fructose, sucrose]

Disaccharides= 2 monosacharides

Starch…
Oligosaccharides= 3-10 monosaccharides
Polysaccharides= >10 monosaccharides

Dietary fiber…
Non-starch oligo or poly

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Describe the amino acid structure

A carbon surrounded by an amino group, a carboxylic acid group, a hydrogen and a differing side chain (R)

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What are the different types of Lipids?

Simple lipids (triglycerides), compound lipids (phospholipids, glycolipids), derived lipids (FAs, seroids [cholesterol])

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Glycolysis

Aerobic conditions vs anaerobic conditions (what is the product of each)

Describe aerobic glycolysis

Aerobic conditions produce pyruvate and anaerobic conditions produce lactate

One molecule of glucose is converted to 2 molecules of pyruvate, generating 4 ATP (but 2 ATP are used so end up with 2 ATP total)

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Citric Acid (Kreb’s) Cycle

What is first formed from the pyruvate molecules created in glycolysis? And what can happen once it is formed?

In the presence of O2, what happens to the molecule discussed above and where does it happen?

What is the total yield from 1 glucose molecule (2 pyruvate molecules) after the Kreb’s cycle?

Acetyl CoA (Once this is formed, aerobic {Kreb’s] or anaerobic [fermentation] respiration can occur)

Acetyl CoA enters the Kreb’s cycle in the mitochondria matrix and is oxidized to CO2 and reduces NAD to NADH. NADH is used by the electron transport chain.

6 NADH, 2 FADH2 and 2 ATP

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Describe the process of oxidative phosphorylation (and where is it?)

How much ATP is produced?

Oxidative phosphorylation occurs in the mitochondrial cristae and there is a proton gradient across the membrane by oxidising the NADH produced in Kreb’s and this drives the ATP synthase enzyme

28 or 30

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Describe the structure of ATP

Adenosine (Adenine + Ribose) and 3 phosphates

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Classes of hormones

Amino Acid derivative: (2 types)

Peptide hormone:

Lipid derivative: (2 types)

AA: Thyroid hormone

Peptide: Glycoproteins (TSH and EPO), also small proteins (GH and insulin)

Lipid: Eicosanoids and steroid (from cholesterol)- sex hormones

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In G Protein coupled receptors, what is the…

1st messenger

Effector (enzyme)- give an example

2nd messenger (give example)

Hormone/ ligand

Adenyl cyclase

cAMP or Ca

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3 types of extracellular receptors

GPCR

Enzyme linked receptors

Ion channel-linked receptors

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What do kinases do?

What do phosphatases do?

Activate proteins by adding a phosphate (phosphorylation)

Inactivates proteins by taking off the phosphate (dephosphorylation)

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Path of a motor neuron

1 (what part of brain)
2(where does it travel through)
3(where do their axons synapse and what type of neuron do they synapse onto)

Somatomotor (precentral gyrus)

Corticospinal tract

Axons synapse on the contralateral side of the spinal cord in the ventral horn/ pyramids and onto an alpha-motorneuron

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Where is the location of pre-ganglionic (central) neurons for parasympathetic vs sympathetic

Location of ganglia (postganglionic neurons)

Parasympathetic= lower brainstem and sacral part of spinal cord

Symp= thoracic and lumbar region of spinal cord

Para= close to end organs

Symp= paravertebral chain

What determines the resting potential of a neuron and what does it do

Na/K ATPase

It pumps K into the cell and Na out

What is ionotropic and metabotropic receptors?

Ionotropic= when agonist binds, it stops or promotes influx or eflux of ions (NT depolarise or hyperpolarise neuron this way)

Metabotropic= GPCR

Main Neurotransmitters:

Amino Acids: (2)

Monoamines: (1)

Catecholamines: (2)

GABA and Glycine

Acetylcholine

Adrenalin and Noreadrenalin

Pharmacodynamics=

Pharmacokinetics=

(and their acronyms)

How drugs affect the body (MOA)

How the body affects the drug (ADME)

Define…

Affinity

Efficacy

Potency

Affinity= ligand’s ability to bind to receptor

Efficacy= ligand’s ability to activate receptor

The relative amount of a drug that has to be present to achieve a desired effect (depends on affinity and efficacy)

What can a dose-response curve tell us?

What is Emax and EC50?

Can compare the response of multiple drugs with of the same conc

Emax= maximal response a drug can produce

EC50= conc of a drug that produces half maximal response

What is a drug's bioavailability? (and equation)

The proportion of the administered dose that reaches the systemic circulation FG X FH Fraction absorbed from the GIT (FG) X fraction escaping first pass metabolism (FH)

Classes of microbes: Acellular (example) cellular (2 types and their examples)

Acellular= viruses Cellular= prokaryotes (achaea and bacteria) AND eukaryotes (protists, fungi, plants and animal)

Which ventricle pumps out more blood? What determines this?

They have the same output, the right just pumps it out with much less pressure cause doesn't have to go as far Frank starling law

What are the percentages of water in each compartment... Makes 60% of body weight Intracellular: ___ Extracellular: ___ divided into _____ (__%) and ____ (__%)

Intracellular= 40% Extracellular= 20% - Interstitial fluid and lymph is 15% - Plasma fluid or intravascular fluid is 5%

Describe baroreflex

Arterial pressure falls, baroreceptor firing falls, inhibition of cardiac vagal neurons and activation of cardiac sympathetic neurons= Ach release down and NA release up= vasoconstriction and increased HR= arterial pressure rises

What are the compensatory mechanisms for haemorrhage? (3)

Haemostasis (fixing the hole- clot, platelet, vasoconstriction in area) Restoration of blood vol Restoration of blood pressure

The membrane potential is the electrical potential difference across the membrane. What is the primary determinant of membrane potential when a neuron is at rest?

Leaky potassium channels

SA node (pacemaker) action potential... at -60mV, voltage gated channels called ___ channels open, allowing __ influx and __ efflux As the SA nodal cell gets less negative, those channels close and voltage gated __ channels open so influx of __ into cell which gets the membrane potential to the threshold of ___ A different set of voltage gated __ channels open and causes the membrane to shoot up At the peak, those channels close and ___ channels open causing repolarisation

If channels open allowing Na in and K out Ca channels open so influx of Ca which brings it to threshold of -40mV Ca channels K channels open

SA node --> (atria) --> ___ node --> _____ --> ____ --> _____ --> both ventricles

SA node, atria, AV node, atrioventricular bundle, bundle of his, purkinje fibres

Ventricular muscle cell action potential: Resting transmembrane potential: ___ mV, determined by ___ conductance Small initial depolarisation from pacemaker cell brings it to the threshold of ___ mV Phase 0: (____ due to __ channels) Phase 1: (____ due to ___ channels) Phase 2: (___ due to __ channels) Phase3: (___ due to __ channels) Phase 4: what is it

-90mV K- conductance -80mV is threshold Phase 0: rapid depolarisation, fast gated Na channels open Phase 1: peak/ overshoot, Na channels close and K channels open to let K out of cell Phase 2: plateau, Ca channels open so Ca comes into cell and K still going out so stays here for a while Phase 3: repolarisation, Ca channels close, delayed K channels open so large efflux of K ions Phase 4: resting potential

Contracted initiated by what in... Skeletal muscle Cardiac muscle Smooth muscle (specifically blood vessels)

Skeletal= Ach Cardiac= electrically from SA node Smooth= NA

Describe the structure of Actin Describe myosin

F-actin (double strands) wrap around strands of tropomyosin which have troponin bound (in absence of Ca) which shields actin active sites so they can't bind with myosin Myosin heads have ATPase activity and when attached to actin, they powerstroke which causes contraction

How Ca increase occurs in skeletal myocytes.... 1) Arrival of AP 2) Activation of ____ receptor (what is it and where is it?) 3) Activation of ___ receptor (what is it and where is it?)

2) DHP receptor (membrane Ca channel coupled to Ryr) | 3) Ryanodine receptor (RyR) (Ca channel located on sarcoplasmic reticulum that releases Ca into cytoplasm)

How Ca increase occurs in cardio myocytes... 1) During plateau phase of AP, Ca ions enter via _____ channels 2) Increase in Ca activates ____ receptors on the ____ 3) Massive increase in Ca with positive feedback How are Ca ions removed from cytosol in diastole? (2 things)

1) voltage sensitive Ca channels (CIRC) 2) RyR on SR Ca pump AND Ca/Na exchanger (uses energy of Na conc gradient and pumps Na in and Ca out)

Exercise Pressor Reflex... What is it? What are the 2 components of EPR?

When skeletal muscles start contracting, signals get sent to the medulla and this causes a rise in BP Muscle mechanoreflex (stretch) Muscle metaboreflex (biproducts produced from working muscles)

What is the Bainbridge reflex?

Atrial reflex- when there is too much blood coming into the atria, activation of stretch/ volume receptors causes an increase in HR to pump the blood away from this area

Types of hypersensitivities... Type 1: Type 2: Type 3: Type 4:

Type 1: IgE medicated, antibodies bind to soluble particles (pollen, dust, animal particles) and then mast cells come and release histamine Type 2: IgG and IgM bind to self cells and cause an immune response to cells in the body (red blood cells) Type 3: Antigen-Antibody complexes form in blood vessel walls and cause complement cascades and neutrophils release toxic content that cause lots of inflammation Type 4: T cell mediated (TH1, TH2, CTL), delayed hypersensitivity, reject transplant

Different types of Antibodies and a bit about each

IgE= allergy, mast cells release histamine IgM= first to appear at sight of infection, acute IgG= chronic IgA= present in breast milk, mucus and blood IgD= differentiation of B lymphocytes

What are the 2 antigen presenting cells and what do they do?

The antigen presenting cells (macrophages and dendritic cells) phagocytize invaders and present antigenic bits on their cell surface on a nice attractive MHC “platter”. This presentation stimulates a response from antigen-specific lymphocytes.

Cholinergic vs adrenergic receptors: Adrenergic: Alpha 1: what does it cause Alpha 2: what does it cause Beta 1: where does it affect and what does it cause Beta 2: where does it affect and what does it cause Cholinergic Muscarinic: Nicotinic:

A1: constriction of blood vessels in the periphery A2: negative feedback so stops the release of NA B1: heart and kidneys, increases HR, contractility and renin so increased BP B2: lungs, bronchodilation ``` Muscarinic= heart, decreased HR and force of contraction Nicotinic= smooth muscle constriction ```