Physio1-Exam4

What are the 3 major components of the cardiovascular system?

-Heart: 2 pumps and 2 circuits (heart -> lung, heart -> body)

-Vessels: Transform pulsatile flow into continuous flow

-Blood: Holds nutrients, oxygen, and waste

Why is convective flow needed in the cardiovascular system?

-Convection is the movement of material by flow.

-Needed because diffusion is not enough to bring blood and oxygen to the rest of the body.

How is blood flow distributed in arteries in a parallel arrangement across organs?

- Arteries have parallel arrangements.

- Distribution percentages through organs can change (based on resistance).

How does total systemic blood flow equal cardiac output?

-Since the cardiovascular system is a closed loop, total systemic blood flow equals cardiac output.

What are the parts of the heart, and how do they fit into the cardiac cycle?

1. Oxygenated blood comes from the pulmonary vein to the left atrium to the mitral valve to the left ventricle.

2. The left ventricle ejects blood through the aortic valve to the aorta artery.

3. Blood goes through the organ system (parallel arrangement).

4. Deoxygenated blood is collected in the veins to the vena cava.

5. Blood from the vena cava enters the right atrium through the tricuspid valve to the right ventricle.

6. The right ventricle ejects blood through the pulmonary valve to the pulmonary artery.

7. Blood enters the lungs and becomes oxygenated.

What are the locations of the jugular, carotid, and femoral arteries?

-Jugular: Internal and external jugular veins drain deoxygenated blood from the head and neck to the heart. Located in the neck (more outward).

-Carotid: Common, internal, and external carotid arteries supply blood to the brain and face. Located in the neck (more inwards).

-Femoral: The Femoral artery supplies the lower limbs. Located in the upper thighs/pelvis.

What does systole mean?

Contraction

What does dystole mean?

Relaxation

What are the similarities and differences between the 4 valves of the heart?

-Mitral (bicuspid) valve: Atrioventricular (AV), 2 leaflets. Left atrium -> left ventricle.

-Aorta valve: Semilunar valve, 3 leaflets. Left ventricle -> aortic artery.

-Tricuspid valve: Atrioventricular (AV), 3 leaflets. Right atrium -> right ventricle.

-Pulmonary valve: Semilunar valve, 3 leaflets. Right ventricle -> pulmonary artery.

What are the similarities and differences between cardiac muscle and skeletal or smooth muscle?

-Similarities: Striated, have sarcomeres, contract in response to Ca2+, and use tryponin c and trypomyosin.

-Differences: Smaller muscle fibers, have 1-2 nuclei instead of many, branch, have intercalated disks, are highly aerobic, do not use recruitment and summation (magnitude of produced tension proportional to intracellular Ca2+), and different T-tubule to SR structure.

What are the structure of intercalated disks?

-Junctions of cardiomyocytes with neighboring cells.

-Allow cells to be strong and electrically synchronized.

-Contains three cell junction types.

-Gap junctions: electrically coupled cells, connexin channels.

-Adherens junctions: mechanically couple cells, link cells together, and anchor to actin filaments.

-Desmosomes: mechanically couple cells, codherin plaques anchor cells together at desmin filaments.

What is the process of excitation-contraction coupling for cardiac muscle and distinguish this process from in skeletal and smooth muscle?

1. Depolarization of the myocardial cell membrane spreads inside the cell through T-tubules by opening L-type Ca2+ channels (DHPRs).

2. Intracellular Ca2+ increases, triggering the release of Ca2+ from the SR through ryanodine receptors (calcium-induced calcium release).

3. Calcium increases enough to bind to troponin C, shifting tropomyosin so myosin ATPase can form a cross-bridge with actin.

-Cardiac cells need extracellular Ca2+. DHPRs and RYR are different isoforms.

Can cross-bridge activation be varied by changing [Ca2+ ] in cardiac muscles only?

Change Ca2+ transient (pulse) size, myofilament sensitivity, or amount of Ca2+ stored in SR.

What is the length-tension relationship in cardiac muscle, and how does it compare to that for skeletal muscle?

-Around length of 2.2 um.

-Increased length increases Ca2+ sensitivity of troponin C and Ca2+ release from the SR.

-Cardiac muscles have a steeper curve and have a faster passive tension.

What are the effects of the sympathetic nervous system on cardiac muscle?

Increased contractility, increased heart rate, and increased conduction velocity.

What are the effects of the parasympathetic nervous system on cardiac muscle?

Decreased contractility, decreased heart rate, and decreased conduction.

What are the mechanism by which the sympathetic nervous system act on cardiac muscle (neurotransmitter, receptor, intracellular pathway)?

-Uses norepinephrine on beta1 adrenergic receptors.

-The activated receptor (Gs protein) activates adenyl cyclase, which raises CAMP activity.

-CAMP activates PKA, which phosphorylates many things (L-type channels, ryr receptors, phospholamban, troponin I, and Ifunny).

-Raises Ca2+ and Ifunny influx.

What are the mechanism by which the parasympathetic nervous system act on cardiac muscle (neurotransmitter, receptor, intracellular pathway)?

-Uses acetylcholine on M2 muscarinic receptors.

-Activated receptor (Gi protein) inhibits adenyl cyclase, opposing sympathetic effects.

-Lowers Ca2+ and raises K+ influx.

How can heart function be modeled using the Law of Laplace for a thin-walled sphere?

Treat the ventricle as a thin-walled pressure vessel and relate pressure to wall force.

Does the ventricular wall thicken to generate more power in some cases, but this eventually leads to pathological loss of elasticity?

Thickening allows for the induction of greater pressure to overcome atrial pressure and open the aortic valve.

Where are the leads of Eindhoven's triangle go on the body for ECG recording?

-Right arm, left arm, and left leg.

-Equilateral triangle with a heart in the middle.

-Lead 2 (RA and LL) is usually used to observe the ECG.

What are the parts of the ECG recording, and how do they relate to the cardiac cycle (P-wave, PR interval, QRS complex, T-wave, QT segment, ST segment)?

-P-wave: depolarization of atria. Atrial contraction.

-PR interval: time from initial depolarization of atria to initial depolarization of ventricle. AV node delay. Ventricular filling is complete.

-QRS complex: three waves representing the depolarization of the ventricles. Ventricles start to contract.

-T-wave: repolarization of the ventricle. The ventricle relaxes.

-QT segment: time from first ventricle depolarization to last ventricle repolarization. Entire ventricular systole.

-ST segment: Plateau of ventricular action potential. Ventricle ejects.

What is the relationship between stroke volume, end diastolic volume, and end systolic volume?

-Stroke volume = volume ejected in one ventricular contraction (in volume of blood).

-End diastolic volume = volume in one ventricle before ejection.

-End systolic volume = volume in one ventricle after ejection.

-SV = EDV-ESV

What is the typical cardiac output?

5 L/min

For a 70 kg man, what is the stroke volume and heart rate?

-SV = 70 mL

-HR = 72 beats/min

At steady state, does cardiac output equal venous return?

Blood volume out of the heart = blood volume into the heart

What is the Frank-Starling relationship?

-Links right atrial pressure to cardiac output.

-Stroke volume is determined by left ventricular contraction.

-The more you fill the heart, the harder it contracts until it cannot.

-Ventricle more stretched = higher blood volume = higher isometric pressure.

What do ventricular pressure-volume loops represent?

1-2. Isovolumetric contraction: Both valves are closed, but pressure rises as the ventricle contracts until the aortic valve opens.

2-3. Ventricular ejection: The Aortic valve opens, and blood ejects when left ventricular pressure is greater than aortic pressure.

3-4. Isovolumetric relaxation: Both valves are closed, and pressure drops as the ventricle relaxes.

4-1. Ventricular filling: Mitral valve open, and the ventricle fills with blood when left atrial pressure is greater than left ventricular pressure.

-Higher preload = higher EDV.

-Higher preload and afterload = lower stroke volume.

What are the different definitions of cardiac work (e.g., pressure work, volume work)?

-Cardiac minute work (P) = cardiac output (d/t) * aortic pressure (F)

-Pressure work = aortic pressure, needs more O2, higher percentage of cardiac energy consumption.

-Volume work = cardiac output, passive stretch.

How does myocardial oxygen consumption relate to cardiac work?

- Pressure work needs more O2 than volume work because it needs ATP to contract, as compared to the passive stretch of volume work.

-O2 consumption correlates poorly with cardiac output (volume work).

How do you apply the Fick Principle (conservation of mass of O2 in the body)?

Assume that at steady state, the cardiac outputs of the right and left ventricles are equal.

What are all the steps in the cardiac cycle, including how they relate to blood flow through the heart, valves opening/closing, heart sounds, pressures, and volumes in the heart chambers, venous pulse, and electrical signals on an ECG?

1. Atrial contraction: Left atrium contracts to fill the left ventricle (mitral valve opens - 4th heart sound). Left atrium pressure is greater than left ventricle pressure. P wave.

2. Isovolumetric ventricular contraction: Left ventricle contracts (mitral and tricuspid valves close - 1st heart sound). Left ventricular pressure is greater than left atrium pressure. Beginning of the QRS complex.

3. Rapid ventricular ejection: Left ventricle contracts and blood is ejected (aortic valve opens). Aortic pressure increases due to the blood, and left atrial pressure rises as it is filled. End of ST.

4. Reduced ventricular ejection: Ventricle pressure falls with relaxation, and aortic pressure reduces as blood flows out of the aorta. Starts at the beginning of the T wave.

5. Isovolumetric ventricular relaxation: Ventricle fully repolarizes, causing ventricular pressure to drop dramatically (aortic valve closes slightly before pulmonary valve - 2nd heart sound). Aortic pressure shows a blip.

6. Rapid ventricular filling: Left ventricular pressure falls below left atrial pressure, causing the mitral valve to open (rapid flow of blood from atrium to ventricle - 3rd heart sound).

7. Reduced ventricular filling: Final ventricular filling occurs at a reduced rate.

What are the specialized conducting cells in the heart (SA node, atrial internodal tracts, AV node, bundle of His, Purkinje system), and how do they coordinate the timing of the heartbeat?

-SA nodes generate action potentials spontaneously to maintain a beating heart.

-Atrial internodal tracts (atrial muscle) rapidly conduct impulses across the atria to the AV nodes.

-The AV node delays the impulse for ventricular filling.

-Bundle of His carries the impulse to the ventricles.

-Purkinje fibers rapidly activate ventricles for synchronized contraction.

-Ventricular muscles have a longer period of experiencing the action potential to efficiently pump blood.

What are the differences in action potentials produced in the atria, ventricles, SA node, and Purkinje fibers?

-Atria, ventricles, and Purkinje fibers: Have sustained plateaus and stable resting potentials. Resting potential of ~85 mV. Upstroke, initial repolarization, plateau, repolarization, and electrical diastole.

-SA node: Spontaneously generates action potential and unstable resting membrane potential. Resting potential of ~60 mV. Upstroke, repolarization, and spontaneous depolarization.

What are the different types of ion channels and currents driving cardiac action potentials?

-Phase 0: Upstroke: Transient increase in inward Na+ conductance causes depolarization.

-Phase 1: Initial repolarization: Na+ stops, K+ in. Inward > outward. Outward K channels start opening.

-Phase 2: Plateau: L-type Ca2+ channels open, causing Ca2+ in. Balanced by outward K. Inward = outward.

-Phase 3: Repolarization: L-type Ca2+ channels close, decreasing inward Ca2+. Outward K+ increases. Outward > inward.

-Phase 4: Electrical diastole: Out K+ balanced by in Ca2+ and Na+. Inward = outward.

-Phase 0: Upstroke: Inward Ca2+ with opening of L-type and T-type channels. Delayed inward K+ channels give pacemaker activity.

-Phase 3: Repolarization: Outward K+ increases.

-Phase 4: Spontaneous Depolarization: Inward Na+ (funny current) causes slow depolarization.

What is the absolute refractory period?

The longest duration of an action potential.

What is the effective refractory period?

Time after an action potential before Na+ channels are recovered.

What is the relative refractory period?

Time between ARP and when the membrane potential is completely repolarized. An action potential is possible, but it will need a high stimulus and will have an abnormal shape.

What is the supranormal period?

Time between the end of RRP (~70 mV) and depolarization back to -85 mV when the cell is more excitable.

What is the basic cellular composition of blood?

-Plasma: 55% (91% water, 7% blood proteins, and 2% nutrients).

-Cellular components: (45%, buffy coat with white blood cells and platelets (small amounts) and red blood cells (large amounts).

What is a hematocrit?

-Ratio of red blood cells to total volume.

-Hematocrit levels determine certain blood disorders, blood velocity, flow properties, and the ability to carry oxygen.

How do pressure differences drive blood flow?

-Blood flows from high pressure to low pressure.

-The heart creates pressure gradients.

What is the normal range for systolic blood pressure?

90-120 mmHg

What is the normal range for diastolic blood pressure?

60-80 mmHg

How do you calculate pulse pressure?

-Rise of pressure from diastolic to systolic levels.

Change in pulse pressure = Psystolic - Pdiastolic

How do you calculate mean arterial pressure?

-Average pressure in the complete cardiac cycle.

PA = diastolic + Pulse pressure/3

What is the structure/anatomy/functions of arteries?

-Blood away from the heart.

-Has tunica externa (collagen, elastin, and fibroblasts), tunica media (smooth muscle pericytes), and tunica interna (endothelial cells).

-Thick first two layers and circular cross-section.

What is the structure/anatomy/function of veins?

-Blood to the heart.

-Has tunica externa (collagen, elastin, and fibroblasts), tunica media (smooth muscle paricytes), and tunica interna (endothelial cells).

-Thin first two layers and elliptical cross-section.

What is the structure/anatomy/function of capillaries?

-Connect arterioles to venules.

-Has a layer of endothelial cells.

-Usually can only hold one blood cell.

How do pressure waves propagate down the arterial tree?

-Pressure waves are generated from the heart and propagate down the arterial tree at 5-8 m/s (faster than blood flow at 0.2 m/s).

-As pressure pulse propagates, vessels change size and compliance.

What is the dicrotic arch, and how does it propagate down the arterial tree?

-Dicrotic arch/notch is the closing of the aorta valve.

-It dampens with distance from the heart.

How do pathological conditions and age affect vessel compliance and blood pressure?

-Age: lower vessel compliance and higher blood pressure.

-Arteriosclerosis (hardening of arteries due to plaque buildup): lower vessel compliance and higher blood pressure.

-Aortic stenosis (aortic valve narrows): lower stroke volume and lower blood pressure.

How is blood pressure measured using a sphygmomanometer and by listening to the Korotkoff sounds?

-Cuff inflates to block the brachial arteries.

-When cuff pressure is just below systolic pressure, blood comes back into the artery, producing the first Korotkoff sound that indicates systolic pressure.

-Sound gets louder until brachial artery pressure lowers near diastolic pressure, where sound gets muffled and disappears.

What is laminar flow?

All streams run in parallel in the axial direction and do not mix.

What is turbulent flow?

Streams run both radially and axially and mix.

What does a Re > 3000 tell you?

Turbulent flow

What does a Re < 2000 tell you?

Laminar flow

What are venous and cardiac function curves, and where on the graph is the steady state cardiac operating?

The cardiac operating point is where the vascular and cardiac function curves intersect at steady state.

What is mean systemic pressure?

-When the venous return is zero.

-Typically around 7 mmHg.

What is total peripheral resistance (TPR) and how does it relate to cardiac output?

-The overall resistance (sum of all vascular resistance) to blood flow.

-Higher TP = lower cardiac output

-Lower TP = higher cardiac output

What is the cardiac operating point is and how does it relate to contraction, TPR, right atrial pressure, blood volume, and venous return?

-Where cardiac output = venous return.

-Higher contraction = lower cardiac output and lower right atrial pressure

-Higher TPR = lower cardiac output and higher right atrial pressure

-Higher blood volume = higher cardiac output and higher right atrial pressure

-Higher venous return = higher cardiac output and higher right atrial pressure

How does the baroreceptor reflex act to regulate blood flow?

-Baroreceptors are pressure sensors that sense changes in arterial wall stretch in the carotid sinus and aortic arch.

-They relay pressure change information through CNIX (glossopharyngeal) and CNX (vagus).

-The body's mechanism for short-term blood pressure regulation to keep blood flow to the brain and vital organs stable during sudden changes.

How does the Renin-Angiotensin-Aldosterone system act to regulate blood flow?

-Regulates mean arterial pressure by regulating blood volume.

-Regulated hormonally (slower than baroreceptor reflex).

-Increased blood volume, vascoconstriction, and sodium/water retention.

What are additional mechanisms to control blood pressure?

-Chemoreceptors in carotid and aortic bodies and the brain are sensitive to the pressure of O2 and CO2, and pH.

-ADH secretion from the hypothalamus.

-Cardiopulmonary (low-pressure baroreceptors) in veins, atria, and the pulmonary artery.

How does the baroreceptor reflex act during hemorrhage?

-The loss of blood volume decreases mean arterial pressure.

-Baroreceptors try to raise the pressure back to normal by increasing cardiac output, arterial constriction (higher TPR), and venous constriction.

What is the Valsalva Maneuver?

-How to test if a baroreceptor works on someone.

-forcefully exhaling through a closed airway to increase thoracic pressure.

-Baroreceptors should increase heart rate.

What are the different types of capillaries?

-Continuous: most abundant, 1-3 endothelial cell layer with basement membrane, and form tight junctions.

-Fenestrated: In tissues involved with tissue exchange, it has fenestrae gaps in capillary walls for fluid exchange.

-Discontinuous: In the liver and spleen (organs that transfer proteins and cells), there are large gaps in the capillary wall and basement membrane.

Every cell in the body is within --- of a capillary?

100 μm

What are the mechanisms by which exchange of solutes and gases crosses the capillary walls?

-Passive diffusion: movement of molecules down a concentration gradient across the capillary wall.

-Bulk fluid flow: movement of large volumes of fluid and dissolved solutes through capillary pores driven by pressure gradients.

-Transcytosis: transportation of substances across endothelial cells through vesicles (endocytosis-into and exocytosis-out).

What is the role of aquaporins in the capillary walls?

Aquaporins are water channel proteins embedded in the cell membranes that allow for rapid water movement.

What is filtration?

Net fluid movement out of a capillary (starling > 0).

What is absorption?

Net fluid movement into the capillary (straling < 0).

What are the Starling forces?

-Kf = hydraulic conductance; how easily fluid passes capillary walls.

-Pc = hydrostatic pressure (favors filtration)

-Pi = interstitial hydrostatic pressure (normally 0 or slightly negative)

-pi c = colloid osmotic pressure (lower filtration, determined by protein concentration in blood)

-pi i = interstitial osmotic pressure (higher filtration, determined by protein concentration in extracellular space, normally very low)

What is the extravascular circulation (lymph)?

-The lymphatic system helps drain fluid in tissue (return interstitial fluid and proteins to the vasculature).

-One way (in, not out).

-Driven by muscle contraction.

What are the mechanisms by which local blood flow through capillaries is regulated?

-Autoregulation: Adjusting blood flow by changing the arterial resistance of organs.

-Active hyperemia: Adjusting blood flow to meet metabolic demands.

-Reactive hyperemia: Adjusting blood flow to compensate for prior periods of low blood flow.

-Myogenic hypothesis: When smooth muscle cells are stretched by high pressure, they contract in opposition to maintain constant flow.

-Metabolic hypothesis: O2 delivery to tissue can be matched to its consumption by adjusting arterial resistance.

What is the role of the SRY gene in sex determination?

-Sex-determining region of the Y chromosome.

-At week 7 of gestation in males, the gene induces testicular development with SOX9 transcription.

-At week 9 of gestation in females, the absence of genes initiates ovarian development.

What are Müllerian ducts?

-In the absence of anti-mullerian hormone (AMH), they develop into female reproductive structures.

-Regress during male development.

What are Wolffian ducts?

-In the presence of testosterone, they develop into male internal reproductive structures.

-Degenerate during female development.

What are common disorders of sexual development (DSDs)?

-46XY genotype: individuals have XY chromosomes but incomplete/atypical masculinization.

-46XX genotype: individuals have XX chromosomes but develop atypical or masculinized genitalia.

What is the hypothalamus-pituitary-gonads signaling axis?

-Hypothalamus secretes GnRH, which causes the anterior pituitary to secrete FSH and LH.

-FSH and LH arrive at the gonads, making them secrete sex hormones (testosterone, estrogen, and progesterone) that will start gametogenesis and other effects on the reproductive tracts and other organs.

-Sex hormones inhibit GnRH secretion and can inhibit or excite LH and FSH secretion.

How does gonadotropin secretion change over the life span?

-During fetal life, gondotropin secretion is high.

-During childhood, secretion is very low (FSH>LH).

-During puberty, secretions slowly increase.

-During the reproductive period, women have large cyclic secretion variations with the menstrual cycle (LH >FSH).

-During senescence, gonads become less responsive to gonadotropins, but levels are high (FSH > LH).

What is the role of the hypothalamus-pituitary-gonads signaling axis in puberty?

-Onset marked by pulsatile secretion of GnRH and FSH and LH from the anterior pituitary.

-Large pulses of LH during REM sleep.

-Pulsatile FSH and LH induce the gonads to produce sex hormones.

What changes occur in males during puberty?

-Increasing synthesis and secretion of testosterone by Leydig cells increases the number of seminiferous tubules where sperm are made.

-Growth of testes, prostate, and penis; linear growth spurt; pubic hair growth; lower voice, and initiation of spermatogenesis.

What changes occur in females during puberty?

-Increase synthesis of estradiol (estrogen) by the ovaries.

-Breast development, pubic hair growth, menarche (1st menstrual cycle), and linear growth spurt.

What are the phases and process of meiosis?

1. Interphase: Chromosomes are not visible because they are uncoiled. The cells grow in preparation for division, and DNA is replicated to form duplicated chromosomes.

2. Prophase I: Chromosomes coil, the nuclear membrane disintegrates, spindle fibers form, homologous chromosomes pair up into tetrads, and homologous recombination happens.

3. Metaphase I: Homologous chromosome pairs become aligned at the cell's equatorial plate, and independent assortment occurs.

4. Anaphase I: Chromosome pairs separate to opposite poles. Sister chromatids are attached at centromeres.

5. Telophase I and Cytokinesis: Cytoplasm divides, and the nuclear envelope reforms, causing two haploid daughter cells to separate.

6. Prophase II: Chromosomes coil, the nuclear membrane disintegrates, and spindle fibers form.

7. Metaphase II: Homologous chromosomes are aligned at the cell's equatorial plate.

8. Anaphase II: Chromosomes separate into chromatids to opposite poles. Telophase II and Cytokinesis: Cytoplasm divides, and the nuclear envelope reforms, causing four haploid daughter cells to separate.

-Meiosis has two big phases:

-Meiosis I: One diploid parent divides into two haploid cells.

-Meiosis II: Sister chromatids separate. The two haploid cells divide into four haploid daughter cells.

How many chromosomes do humans have in somatic cells and gametes?

-Somatic: diploid - 46 chromosomes

-Gametes: haploid - 23 chromosomes

When does gametogenesis occur during the lifetime of males and females?

-Females: Start before birth, pause until puberty, stop at menopause.

-Males: Starting during puberty and continuing through life.

What are the major anatomical structures in the male reproductive system?

-Testes: suspended outside the abdomen to function 2C below body temperature.

-Vas deferens: continues behind the urinary bladder base.

-Seminal Vesicle: lies behind the bladder and joins the vas deferens to form the ejaculatory ducts.

-Ejaculatory ducts: enter the prostate gland and join the urethra.

-Prostate gland (doughnut-shaped): below the bladder and surrounding the upper urethra. Secretes fluid through openings.

-Urethra: enters the penis.

-Paired bulbaurethral glands: drain into the urethra after leaving the prostate.

-Testes:

-Seminiferous tubules: produce a lot of the sperm.

-Rete testis exits the testis and enters the epididymis.

-Epididymis: loosely attached to the outside of the testis.

-Vas deferens: thick tube with smooth muscles.

What are the processes and phases of spermatogenesis?

-Begins at puberty, where mature cells are generated.

-Starts with mitosis of undifferentiated stem cells.

-Spermatogonia (46 chromosomes, 2 chromatids) -> primary spermatocytes (46 chromosomes, 2 chromatids) -> secondary spermatocytes (23 chromosomes, 2 chromatids) -> spermatids (23 chromosomes, 1 chromatid) -> spermatozoa (mature sperm, 23 chromosomes)

What is the sperm route?

Seminiferous tubules -> efferent ducts in epididymis -> vas deferens -> ejaculatory duct (vas deferens and seminal vesicle) -> prostate -> urethra

What is the composition and function of seminal fluid?

-Semen = 10% sperm and 90% fluid from vesicles and ducts

-Fluid = nutrients, buffers, chemicals, and prostaglandins (helps with penetration and propulsion)

What is the process of sperm capacitation?

-Takes 4-6 hours in the female reproductive system after ejaculation.

-Inhibitory factors are washed away, cholesterol is withdrawn from the sperm membrane, and surface proteins are redistributed to form the acrosome.

How is testosterone synthesized and secreted, and what are its actions in males?

-Synthesized and secreted from Leydig cells.

-Have 17 Beta-hydroxysteroid dehydrogenase, which converts the majority of testosterone.

-Differentiation of male reproductive parts, increased muscle mass, growth spurt, deepening of voice, spermatogenesis, negative feedback to the pituitary, and libido.

What are the major anatomical structures in the female reproductive system?

-Two ovaries

-Fallopian tube, uterus, cervix, and vagina.

What are the processes and phases of oogenesis?

-Production of haploid gametes in females

-Full process not complete until fertilization

-During fetal life, oogonia become primary oocytes (46 chromosomes, 2 chromatids)

-Before ovulation, primary oocytes undergo meiotic division to a secondary oocyte and a first polar body (23 chromosomes, 2 chromatids).

-After fertilization, the secondary oocyte undergoes meiotic division to become the ovum and second polar body (23 chromosomes).

When does oogenesis take place during a female's life?

-Primary oocytes are produced before birth (and arrest in prophase I).

-During puberty, the primary oocyte becomes a secondary oocyte. The secondary oocyte is ovulated if fertilized.

-Oogenesis ends during menopause.

What are the structure and functions of the ovary and ovarian follicles?

-Follicle = functional unit of the ovary

-Ovarian follicle: one oocyte surrounded by endocrine cells. Provides nutrients to developing oocytes at ovulation. Releases oocytes at ovulation.

What are the processes and phases of folliculogenesis?

-Primordial follicle (present at birth) -> primary follicle -> preantral follicle -> early antral follicle (antrum forms) -> mature follicle (cumulus oophorous forms)

How does the follicle change with the menstrual cycle?

-At the beginning of the ventral cycle, 10-25 preantral and early antral follicles start developing into large antral follicles.

-One week in, only the dominant follicle continues to develop.

-Near ovulation, an oocyte emerges from meiotic arrest to complete the first meiotic division and become a primary oocyte.

What is the process of ovulation?

-Day 14 of the 28-day menstrual cycle.

-Where the dominant follicle ruptures.

-Secondary oocytes enter the fallopian tube.

-If fertilized, the oocyte will complete meiosis.