Phys Exam 3 (unfinished)

HPG axis order

GnRH from hypothalamus → LH and FSH from anterior pituitary → sex hormones from gonads

GnRH function

Stimulates anterior pituitary to release LH and FSH

LH function (female)

Stimulates thecal cells to produce androgens and triggers ovulation

FSH function (female)

Stimulates granulosa cells and aromatase to convert androgens into estrogens

Thecal cells

Produce androgens in response to LH

Granulosa cells

Convert androgens to estrogens using aromatase

Aromatase

Enzyme that converts androgens into estrogens

LH surge causes

Ovulation

Ovulation timing

Middle of the cycle

Phase where progesterone is highest

Luteal phase

Progesterone function

Maintains endometrium and makes it secretory

Secretory endometrium

Thick vascular lining ready for implantation

Low estrogen feedback

Negative feedback on hypothalamus and pituitary

High estrogen feedback

Positive feedback triggering LH surge (then ovulation)

Inhibin function

Inhibits FSH release

Photoperiod definition

Day length used as reproductive cue

Photoperiod importance

Most reliable environmental signal

Iteroparous species

Reproduce multiple times

Semelparous species

Reproduce once across lifetime

Offspring provisioning

Resource transfer from parent to offspring

Embryonic diapause

Temporary pause in development until conditions are favorable

Silkworm diapause

Eggs laid in autumn, cold weather required to terminate diapause and resume development in spring

Short day breeders

Reproduce when day length decreases

Genetic sex determination

Sex determined by chromosomes

Temperature sex determination

Sex determined by temperature

Sequential hermaphroditism

Individual changes sex during lifespan

LH acts on male ____

Leydig cells

Leydig cells function

Produce testosterone

FSH acts on male

Sertoli cells

Sertoli cells function

Support sperm development

Sertoli cells do not ___

Produce testosterone

Testosterone function

Supports spermatogenesis and male traits

Fetal testosterone

Required for male development

Oocyte at fertilization

Blocks additional sperm and completes meiosis

hCG function

Maintains corpus luteum

First pregnancy hormone

hCG

Progesterone

Maintains uterine lining during pregnancy

Estrogen during pregnancy

Increases gap junctions and oxytocin sensitivity

Birth trigger

Cervical stretch and pressure —> brain releases oxytocin

Oxytocin birth

Stimulates contractions

Lactation order

Suckling to oxytocin to contraction to milk ejection

Prolactin stimulates ___

Milk production

Oxytocin lactation

Milk ejection

Breastfeeding effect

Due to ____, prolactin suppresses ovulation by inhibiting GnRH

Right heart pumps

Deoxygenated blood to lungs

Left heart pumps

Oxygenated blood to body

Blood flow right side

Body to right heart to lungs

Blood flow left side

Lungs to left heart to body

Gap junctions in the heart

Allow electrical communication

Atrial systole

Contraction of atria

Max ventricular filling

Atrial systole leads to ___

Max blood flow

Ventricular ejection leads to ___

Cardiac cycle order

AV valve open —> filling —> isovolumetric contraction —> aortic valve open —> ejection —> pressure decrease

Isovolumetric contraction

Pressure increases volume constant

Isovolumetric relaxation

Pressure decreases volume constant

Cardiac output

Heart rate x stroke volume

Frank Starling law

More filling leads to stronger contraction

Sympathetic effect

Increases heart rate and contractility

Parasympathetic effect

Decreases heart rate

Venous return increase

Vasoconstriction leads to

EKG P wave

Atrial depolarization

EKG QRS

Ventricular depolarization

EKG T wave

Ventricular repolarization

Pacemaker potential

Slow depolarization before action potential

What initiates pacemaker potential in SA node

Funny Na+ channels open

what is the voltage gated Ca²⁺ (T type) channels role in pacemaker cells in SA node?

Open to help reach threshold

Voltage gated Ca²⁺ channels (L type) role in pacemaker cells in SA node

Depolarization

K+ role in pacemaker potential in SA node

Repolarization

Pacemaker order

funny Na⁺ —> T-Ca²⁺ —> L-Ca²⁺ —> K⁺

ACh effect on pacemaker cells

Decreases heart rate and slows pacemaker potential, acts via muscarinic receptors to open K+ channels, inhibits cAMP production

Sympathetic NT

Norepinephrine

First ion depolarization

Na⁺

Plateau phase

Ca influx

Flow increases with ___ and ____

Pressure and radius

Flow decreases with ___ and ___

Viscosity and length

Most important flow factor

Radius

Blood pressure trend

Decreases from arteries to veins

Capillary pressure

Decreases along length

Capillary velocity is ___ + why?

Lowest because capillaries have the greatest total cross-sectional area

Why capillaries slow

Large cross sectional area

Filtration

Fluid leaves capillary

Reabsorption

Fluid enters capillary

Baroreceptors detect ___

Blood pressure

High BP effect

Decreases heart rate

Baroreceptor order

BP increase to firing —> increase to CV center —> PNS —> heart rate decrease

Low BP response

Sympathetic increase to HR increase

Gases move by

Convection and diffusion

Convection

Long distance movement

Diffusion

Short distance movement

Partial pressure

Only free gas contributes

Temp vs solubility

Higher temp lower solubility

CO2 transport

Bicarbonate

Oxygen cascade

PO2 decreases lungs to tissues

Hemoglobin subunits

4

Myoglobin subunits

1

Hemoglobin curve

Sigmoidal

Myoglobin curve

Hyperbolic

Sigmoidal means

Cooperativity

P50

PO2 at 50 percent saturation

Low P50

High affinity