Bioscience flashcards

Pregunta	Respuesta
What are the three general processes of urine formation?	1. Glomerula filtration 2. Tubular reabsoption and secretion 3. Urine processing
Describe glomerula filtration. Why does it occur?	1. Fluid is forced out of glomerulus (a tuft of capillaries) into the Bowman's capsule. 2. The filtrate then passes into the proximal convoluted tubule. This occurs due to differences in the hydrostatic pressure (forces fluid out) and the oncotic pressures (keeping fluid in).
Name the areas of a nephron and their functions.	Glomerulus - Filtration Bowman's Capsule Proximal tubule - reabsorption of protein, glucose, electrolytes. Loop of Henle: Ascending - permeable to ions Descending - permeable to water Distal tubule - reabsorption Collecting duct - urine concentration
The permeability of the collecting duct to water is regulated by what?	Anti-diuretic hormone and aldosterone.
What is the method of action of anti-diuretic hormone (ADH)?	Causes artery constriction and reabsorption of water in the collecting duct by inserting aquaporins (water pores) into the cell membrane.
What is the method of action of aldosterone?	Steroidal hormone. Binds to mineralocorticoid receptor in collecting duct. Increases production of sodium-potassium pumps and sodium protein channels. Increases the osmotic pressure enhancing water absorption by ADH.
What are the three groups of diuretics? Where in the nephron do they act? Give an example of each.	1. Loop diuretics - ascending Loop of Henle (which is permeable to ions) Eg. Furosemide 2. Thiazide diuretics - distal convoluted tubule (Think: D for diuretic = distal!) Eg. Chlorothiazide 3. Potassium-sparing diuretics - act on collecting duct. Eg. Spironolactone
What is particularly important to consider about loop diuretics?	Furosemide toxicity - tinnitus, circulatory collapse, seizures. Arrythmias due to hypokalemia. Interactions with aminoglycoside abx - causing deafness.
What are some of the main indications for loop diuretics?	CHF, ascities with oedema, renal failure, pulmonary oedema.
What is the mechanism of action for potassium sparing diuretics? Give an example. What are some indications for use of a potassium sparing diuretic above thiazide/loop diuretics?	Eg. Spironolactone Competes with aldosterone (steroidal hormone increasing the number of sodium carrier proteins) to block mineralocorticoid receptor therefore reducing production of Na carrier proteins. Indications: when hypokalemia is exceptionally harmful, eg. individuals taking digoxin or amiodarone. HF, hyperaldosteronism (Conn's syndrome)
What are some adverse effects of diuretic therapy?	Potassium loss can cause fatal arrythmia. Drug interaction resulting in toxicity, eg. Digoxin Hypo/hyperkalemia (high/low potassium) Acidosis
Into which areas are the following hormone groups secreted? Endocrine Autocrine Paracrine	Endocrine - released into the blood stream Autocrine - acts on the same cell that secretes it Paracrine - realeased into surrounding tissue
In regulation of BP, what is the second messenger? What is the target?	Seond messenger - Calcium Target - beta 1 adrenergic receptor
Targets tend to be receptors or enzymes. True or false?	True!
Which hormones are secreted by the posterior pituitary?	Oxytocin and Anti-diuretic hormone (ADH)
Which hormones are secreted by the anterior pituitary?	Everything but oxytocin and anti-diuretic hormone! (ADH) ACTH, thyroid stimulating hormone (FSH), gonadotrophic hormone etc.
What is Cushings' disease?	Primary adrenal gland defect or excessive ACTH secretion.
What is Addisons' disease?	Hypoadrenocorticism
What are the endocrine cell types of the pancreas? What is their function?	Alpha cells - secrete glucagon Beta cells - secrete insulin Gamma cells - produce pancreatic peptide Delta cells - secrete somatostatin
Glucose is stored as what?	Glycogen
When blood glucose is low, ______ is broken down by _______ to ______?	Glycogen is broken down to glucose, by glucagon. Think: when glucose is GONE - glucagon!
Blood pressure is controlled by a negative feedback mechanism. True or false?	True! Detected by baroreceptors (pressure receptors) Renin --> Angiotensin --> Aldosterone system
Where is renin secreted from? In response to what?	Renin is secreted by the kidneys in response to low BP or low serum sodium.
Angiotensin II is converted to _____ by _____? ________ can stabilise blood pressure by preventing this.	Angiotensin II is converted to aldosterone by angiotensin converting enzyme (ACE) ACE inhinitors stabilise blood pressure by preventing aldosterone being produced and increasing BP.
Renin cleaves ______ to Angiotensin I?	Angiotensinogen
Where is angiotensin I converted to angiotensin II?	In the lungs.
What is aldosterone?	A steroidal hormone that causes sodium retention.
What is conductive tisssue?	Specialised muscle (less elastic than myocardium) that has the ability to automatically generate an electrical impulse.
What is stroke volume?	Volume of blood ejected from each ventricle on each contraction.
What is cardiac output?	Volume of blood ejected by the heart in one minute.
What is the equation of cardiac output?	Cardiac output = stroke volume x heart rate CO = SV x HR
How many pairs of chromosomes do humans have?	23
What are the nitrogenous bases in RNA?	A C U G Uracil replaces T
What is transcription?	DNA -----> RNA RNA polymerase reads the DNA template strand to make mRNA.
What is translation?	RNA -----> protein mRNA attaches to ribosome. Ribosome reads mRNA and tRNA transports corresponding amino acids to create complementary base pairs.
Define genotype and phenotype?	Genotype - genetic make-up, inherited from parents. Alterations occur at conception. Phenotype: observable characteristics determined by genotype and environment (phenotypic polymorphisms etc.)
What is an allele?	Genes that contain different descriptive data about the same trait, eg. eye colour, blood group, height.
What is co-dominance?	When two alleles are equally dominant. Eg. blood group - A & B forming group AB.
What is incomplete codominance?	Pink flowers! One allele is not completely expressed over another, resulting in a third phenotype. Eg. red & white flowers - pink flowers.
Give an example of a genetic disorder that occurs at the result of a point mutation?	Cystic fibrosis Sickle cell anaemia Long QT
How many chromosomes does a daughter cell produced by meiosis have? Are they haploid or diploid cells? Where does meiosis occur?	23 chromosomes (haploid) In reproductive cells/gonadal.
Define oncotic pressure.	A gradient caused by unequal distribution of macromolecules (eg. proteins & peptides) across a membrane.
Define homeostasis.	Maintenance of a constant internal environment.
What is diffusion? Is this an active or passive process? (Does it require energy?)	Diffusion is the movement of solute from a high concentration to a lower concentration. It is passive, going with the concentration gradient and therefore does NOT require energy.
What are factors that cause fluid extravasation?	Increased BP. Blocked lymph drainage Inflammation Liver failure
What are factors that cause fluid retention?	Hypernatremia (high sodium) Renal failure
Give an example of a positive feedback mechanism?	Childbirth - oxytocin/muscle contractility
Define agonist and antagonist drugs.	Agonist - drug with a high affinity and high intrinsic activity. Antagonist - drugs with a high affinity but no intrinsic activity.
What are the two kinds of antagonist? What do they do?	Competitive antagonist - compete for the same receptor as the agonist. Non-competitive antagonist - bind somewhere other than the natural ligand site and incapacitate receptor.
What is the role of the golgi apparatus?	To produce and mature proteins in collaboration with the endoplasmic reticulum.
Give examples of amine hormones?	Catecholamines Thyroid hormone
The CNS exerts rapid control via impulses and neurotransmitters. True or false?	True!
Calcium is not a secondary messenger. True or false?	False. Calcium is a secondary messenger.
Give an example of an adrenal steroid/mineralocorticoid steroid?	Aldosterone!
What are islets?	Pancreatic cells that are richly vascular so that hormones secreted have rapid access to circulation.
Glucagon is secreted in response to hypoglycemia. True or false?	True.
What is diabetes mellitus?	Beta cell disease. (Pancreatic beta cells secrete insulin.) Type 1 = no secretion of insulin. Type 2 = insufficient or resistance to secreted insulin.
Dendrites conduct nerve impulses ________ the cell body. Axons conduct nerve impulses _______ from the cell body. Towards, away.	Dendrites conduct nerve impulses TOWARDS the cell body. Axons conduct nerve impulses AWAY from the cell body.
Schwann cells facilitate _________ conduction.	Saltatory conduction.
What are the functions of: Bronchi Alveoli Nose	Bronchi - regulates airflow by regulating diameter. Alveoli - remove foreign bodies from air, gaseous exchange surface. Nose - filters and moisturises air.
What are the functions of the two types of alveolar cells?	Type 1 - main respiratory surface (gas exchange) Type 2 - inflammation response, secrete surfactant and clear alveolar sac.
What is FEV1?	The measure of air volume forcefully blown out in one second.

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