Flashcards
Biology exam..
Cards in this deck (86)
- 1Define meiosisChromosome conjugation and two cell divisions
1. DNA in parent cell multiplies
2. Recombines to AAAb, BBBa, aaaa and bbbb
3. Meiosis I produces 2 daughter cells
4. Meiosis II, the 2 daughter cells each produce 2 more cells - 2Define folliculogenisisDevelopment of follicles in ovaries
- 3Name the two ovarian cyclesFollicular phase - before ovulation
Luteal phase - after ovulation - 45 stages of follicle development (brief explanation) from follicular phase to luteal phase1. Primordial follicles 2 mil in ovarian cortex
2. Primary follicles, cells enlarge, zona pellucida forms around oocyte
3. Secondary follicles wall thickens and cell secretes fluid
4. Tertiary follicles - one secondary becomes tertiary at day 10-14 of cycle, has antrum (fluid chamber) and corona radiata (protective layer formed by granulosa cells)
5. Tertiary follicle releases secondary oocyte into uterine tube, start of luteal phase
6. Corpus luteum forms, progesterone, estrogen, relaxin and inhibin secreted, uterine lining matures
7. Corpus luteum becomes corpus albicans scar tissue when no longer needed - 5Define ampullaCentral region of uterine tubes where fertilisation occurs
- 6Define isthmusNarrowest region of uterine tubes where sperm matures
- 73 regions of the uterusFundus: rounded superior portion connecting to tubes
Body: largest portion
Cervix: inferior portion surrounding cervical canal - 83 layers of the uterusEndometrium: simple columnar epithelium. Stratum functionalis shed during menstruation
Myometrium: 3 layers smooth muscle, contacts during childbirth
Perimetrium: outermost layer - 9How does menstruation workIncreased oestrogen thickens endometrium. Spiral arteries constrict due to decreased progesterone and innermost layer sheds.
- 10What is the corpus luteum and what is it responsible for if fertilisation occurs?The leftover of the cell that produced the egg, continues to secrete hormones during pregnancy
- 11Why does menopause occurThere are no remaining follicles to synthesis oestrogen
- 12What does oestrogen do?Development and maintenance of female reproductive organs, feminine secondary sex characteristics
Increase protein anabolism
Lower blood cholesterol - 13What does progesterone do?Works with oestrogen to prepare endometrium for implantation
Prepares breasts to secrete milk - 14What does relaxin do?Inhibits contractions of uterine smooth muscle
Relaxes pubic symphysis and dilates cervix during labour - 15What does inhibin do?Inhibits release of hormones
- 16Structure of vaginaVaginal canal: internal passageway
Fornix: shallow recess around cervix
Rugae: folds in lining when in relaxed state
Hymen - 17Explain the function of the: 1. epididymis 2. ductus deferens 3. seminal glands 4. prostate gland 5. urethra1. site of sperm maturation
2. conducts sperm between epididymis and prostate gland
3. secrete fluid to add to the semen
4. secretes fluid and enzymes
5. conducts semen and urine to exterior - 18What are the dartos and cremaster muscles responsible for?Dartos muscle relaxes in heat, and contracts in cold wrinkling the skin around scrotum and reducing surface area
The cremaster also relaxes in heat and contracts in cold but pulls the testes towards pelvis or drops them away from it - 19Define Panpiniform plexusA network of small testicular veins in the spermatic cord, wrapping around the testicular artery, regulates testicular temperature.
- 20Define tunica albugineaOuter capsule continuous with septa subdividing testes into lobules
- 21Define seminiferous tubulesCoiled tubules within lobules (total length 1/2 mile/testis). Site of sperm production.
- 22Define rete testisCollecting area outside of lobules
- 23Define efferent ductules12 small ciliated ducts which collect sperm from the rete testis and transport it to epididymis.
- 24What are Leydig cells?Found between tubules, secrete testosterone
- 25What are Sertoli cells?Found within tubules, act as support cells, release sperm cells
- 26Define and describe spermatogenesisSperm cell production.
1. Mitosis - somatic cells produce two daughter cells containing 23 identical chromosome pairs (diploid = 2n)
2. Meiosis - end of meiosis II produces 4 haploid (haplo, single) cells each with 23 individual chromosomes. - 27Define and describe spermiogenesisDifferentiation of immature male gametes into physically mature spermatozoa. Discard excess cytoplasm and grow tails. Spermatogenesis and spermiogenesis occur inside tubules and take 9 weeks.
- 28Define spermiationRelease of a sperm cell from Sertoli cell
- 29Describe the structure of spermatozoa including: 1. Acrosomal cap 2. Head 3. Neck 4. Middle piece 5. Principal piece 6. End piece tail1. Contains enzyme
2. Contains nucleus with densely packed chromosomes
3. Contains both centrioles from original spermatid
4. Contains mitochondria, ATP generation for flagellum movement
5. Axoneme surrounded by fibres
6. Narrow tip of flagellum - 30Define capacitation1. Spermatozoa become mobile when in contact with seminal gland secretions
2. Spermatozoa become capable of fertilisation when exposed to female reproductive tract - 31Explain in detail the hormone control of testosterone in the male reproductive system1. Hypothalamus releases gonadotropin-releasing hormone (GnRH)
2. GnRH stimulates anterior pituitary to release Luteinising Hormone (LH) and Follicle Stimulating Hormone (FSH)
3. LH stimulates interstitial cells to secrete testosterone. Testosterone affects libido, bone and muscle growth, accessory glands, secondary male sexual characteristics
4. FSH stimulates nurse cells which promote spermatogenesis, secretes inhibin to feed back to anterior pituitary, and secretes androgen-binding protein (ABP) to stimulate maturation of spermatids - 32Describe structure and function of epididymis6m long coiled duct adhering to posterior of testis. Site of sperm maturation and storage (fertile for 60 days). Sperm undergo functional maturation here for ~2 weeks.
- 33Describe structure of ductus deferensMuscular tube 45 cm long passing up from scrotum through inguinal canal to posterior surface of bladder
- 34Structure of ejaculatory duct2 cm duct formed from ductus deferens and seminal vesicle and passing through prostate to empty into urethra
- 35Describe structure and function of seminal vesiclesPairs found at base of bladder, empty into ejaculatory duct. 60% of semen volume. Secrete alkaline fluid (to neutralise vaginal acid), fructose (for ATP synthesis), prostaglandins (stimulate sperm motility and viability) and fibrinogen (coagulates semen after ejaculation)
- 36Describe structure and function of prostate glandEncircles proximal urethra, below bladder, 2x4x3cm. Secretes milky fluid containing citric acid (for ATP synthesis), enzymes for liquefaction of coagulated semen. 25% of semen volume.
- 37Describe structure and function of bulbourethral glandsNear bulb of penis, secretes alkaline mucous for lubrication into penile urethra.
- 38Outline the process for collecting semen for analysisSample must be examined within 60 minutes and is therefore given onsite. Sperm are very temperature sensitive so should not be refrigerated or kept at room temperature too long. Sperm motility decreases after ejaculation.
- 39Describe the process of atrial systole100msec. 70-80% of ventricular filling occurs due to passive blood flow from veins. Atria contract - increased atrial pressure - flow of last 20-30% of blood volume into ventricles through open AV valves - ventricular filling.
- 40Outline the electrical pathway of the heart from the SA nodeSinoatrial node (top of right atrium) - anterior, middle and posterior internodal tracts (around left and right atrium) - atrioventricular node (bottom of right atrium) - bundle of His (between chambers) - left/right bundle branches (down middle between chambers) - conduction pathways - Purkinje fibres (around ventricles and back up to SA node)
- 41Explain the propagation pathway of cardiac electrical signalsSA node is a pacemaker. Impulse starts there and depolarisation spreads from cell to cell via gap junctions = atrial contraction. The AV node sends the signals down to the apex and back up around the ventricles = ventricles contract from apex upwards.
- 42What is the main difference between the sympathetic and parasympathetic nervous systems in regulating cardiac functions?Parasympathetic controls SA and AV nodes to regulate heart rate. Sympathetic also controls ventricular myocardium contractions to regulate the strength of contractions.
- 43Define and describe ECGElectrocardiogram - measures the electrical activity of the heart
Each part of the ECG wave relates to a specific chamber/action within the heart. - 44What is sinus arrhythmia?Slowing and speeding up of heat rate with expiration and inspiration respectively.
- 45What is an ectopic beat?Occasional extra beat caused by aberrant firing of a group of fibres prior to firing of AV node
- 46What is atrial fibrillation?SA node fires immediately after refractory period, causing fluttering. The ventricles often continue to beat fairly normally so the condition often goes unnoticed.
- 47What is ventricular fibrillation?Cells continuously excited by recycled electrical waves through ventricles leads to ventricle fluttering/shuddering and cardiac arrest.
- 48What is the first sound of a heartbeat caused by?Closure of atrioventricular valves
- 49What is the second, softer sound of a heartbeat caused by?Closure of semilunar valves
- 505 places for listening to the heartAortic - right 2nd intercostal space
Pulmonic - left 2nd intercostal space
Erb's point - 3rd let intercostal space
Tricuspid - lower left sternal border 4th intercostal
Mitral - medial to midclavicular line 5th left intercostal - 51What is congestive heart failure?Failure of either ventricle to eject blood properly.
- 52Define perfusionRate of blood flow per given mass of tissue (ml/min/g)
- 53What is systolic pressure?Highest pressure in systemic arteries (peak in aorta) during ventricular systole
- 54What is diastolic pressure?Lowest arterial pressure during ventricular diastole (just before aortic valve opens)
- 55What is pulse pressure?Difference between systolic pressure and diastolic pressure, important measure of stress exerted on small arteries
- 56What is mean arterial blood pressure? MABPAverage pressure in arteries over the timeframe of one cardiac cycle. Diastolic pressure (Pd) + (1/3 of pulse pressure)
- 57What factors influence vascular resistance?- diameter/radius of vessel
- blood viscosity
- vessel length - 58What influences blood viscosity?Albumin and RBCs i.e. increased with anaemia, decreased with dehydration
- 59If any of HR, SV, or R go up, so does MABP. If any of HR, SV, or R go down, so does MABP....
- 60What happens if MABP is too low?Blood flow to tissues is not adequate - non-delivery of nutrients, oxygen etc. and non-removal of metabolic wastes
- 61What happens if MABP is too high?Tissue damage, in particular heart & blood vessel damage occurs
- 62How do hormones affect blood flow?Adrenaline and noradrenaline: increase heart rate and contractility -
increased cardiac output. Act directly on smooth muscle in blood vessels - vasoconstriction or vasodilation
Vasopressin (antidiuretic ADH): vasoconstriction of all vessels except heart and brain
Angiotensin II: potent vasoconstrictor, increases blood pressure
Atrial natriuretic peptide (ANP): vasodilator - 63How do baroreceptors influence blood pressure?Decreased BP causes rate of signals from baroreceptors to vasomotor centre in medulla of brain to drop, leading to decreased parasympathetic signals and increased sympathetic signals to heart. Leads to increased vasoconstriction, increased CO, increased resistance, increased BP.
- 64How does the chemoreceptor reflex work?Increased CO2, H+ or decreased O2 leads to increased firing of action potentials from receptors along nerves. Leads to decreased parasympathetic stimulation & increased sympathetic stimulation to the heart = increased HR & SV, increased vasoconstriction, increased BP
- 65What are some organs in the endocrine system?Hypothalamus
Pituitary gland
Thyroid gland
Parathyroid glands
Adrenal glands
Pancreas
Gonads - 66Three types of hormonesPeptides (derived from chains of amino acids)
Amines (derived from the amino acids tyrosine and tryptophan)
Steroids (derived from cholesterol) - 67Describe water soluble hormones- amino acid based
- not lipid soluble
- can't diffuse through plasma membrane
- bind to receptors on target cell surface
- use 1st/2nd messenger system - 68Describe lipid soluble hormones- steroids, thyroid hormones and nitric oxide
- diffuse through lipid bilayer of plasmalemma
- bind to receptors within target cells - 69Describe permissive hormone effectsFirst hormone 'allows' second hormone to produce its effect, e.g. epinephrine does not change the rate of energy consumption in a tissue unless thyroid hormones are also present in normal concentrations
- 70Describe additive hormone effectsThe net result when two hormones have additive effects is greater than the effect that each would produce acting alone.
- 71Describe antagonistic hormone effectsWhen two opposing hormones interact, the observed effects are weaker than those produced by either hormone acting unopposed, e.g. insulin and glucagon
- 72Describe integrative hormone effectsDifferent but complementary effects coordinate the activities of diverse physiological systems, e.g. effects of calcitrol (hormonally active vit D) and parathyroid hormone on tissues involved in calcium metabolism.
- 73Describe a 3 step feedback loop- receptor
- control center
- effector - 74Describe hypophysisPituitary gland. Small, oval gland found in a depression in the sphenoid bone. Controlled by hypothalamus. Major integrating link between nervous and endocrine systems. Anterior stimulated by releasing or inhibiting hormones.
- 75What types of hormones does the pituitary gland release?9 peptide hormones - 7 from anterior, 2 from posterior. All bind to membrane receptors and have a second messenger system. Anterior hormones turn on endocrine glands.
- 76What specific hormones does the anterior pituitary release?Adrenocorticotropic hormone (ACTH)
Thyroid-stimulating hormone (TSH)
Growth hormone (GH)
Gonadotropins (regulate gonadal activities)
Follicle-stimulating hormone (FSH)
Luteinising hormone (LH)
Prolactin (PRL) - 77Describe adrenocorticotropic hormone (ACTH)Stimulates release of steroids from adrenal cortex. Released in response to corticotropin-releasing hormone (CRH) from hypothalamus.
- 78Describe thyroid stimulating hormone (TSH)Stimulates release of thyroid hormones (T3, T4). Released in response to thyrotropin-releasing hormone (TRH) from hypothalamus.
- 79Describe growth hormone (GH)Stimulates cell growth and reproduction by stimulating rate of protein synthesis. Release regulated by growth hormone–releasing hormone (GH–RH) and
growth hormone–inhibiting hormone (GH–IH). - 80What are gonadotropins and what do they do?Regulate gonadal activities
eg FSH (follicle stimulating hormone) promotes ovarian follicle development and sperm maturation
LH (luteinising hormone) induces ovulation, promotes secretion of oestrogen, progestins and androgens - 81What does prolactin do?Stimulates mammary gland development and milk production
- 82What does human growth hormone do?Stimulate liver, muscles, bone, cartilage to secrete insulinlike growth factors which promote growth of tissues, cells, protein synthesis, lypolisis, increased BGL
- 83What specific hormones does the posterior pituitary release? Describe their roles.Oxytocin: increased release in childbirth, breastfeeding, sexual arousal, sensory input. Stimulates contraction of uterus and release of milk
Antidiuretic hormone (ADH)/arginine vasopressin (AVP): released in response to increased solute concentration of blood or decreased BP/blood volume. Decreases water lost from kidney, inhibited by alcohol. - 84Structure and location of thyroidButterfly shaped gland located just below larynx. C cells release calcitonin, follicular cells release thyroid hormone.
- 85What do thyroid T3 and T4 cells do around the body?Increase basal metabolic rate, temperature and appetite.
Promotes glucose catabolism for energy, protein synthesis, lipolysis
enhances cholesterol excretion in bile.
Promotes normal cardiac function.
Promotes normal neuronal development and function, enhances effects of parasympathetic nervous system.
Promotes normal skeletal and muscle growth.
Promotes normal female reproductive ability and lactation. - 86—
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- Flashcards on Biology exam.., created by Elizabeth McQuie on 22/06/2016.
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