Physiology Test 2

Define Metabolism

chemical reaction occuring in the body and energy balancing act between anabolism and catabolism

define catabolism

break down complex molecules into smaller units and release energy

define anabolism

combine simple molecules to form body’s complex structural and functional components

define oxidation

removal of electrons, loss of hydrogen

define reduction

gain of electrons, gain of hydrogen

what are the two mechanisms of ATP

• substrate level phosphorylation

• oxidative level phosphorylation

what is substrate level phosphorylation

transferring high energy phosphate group from substrate directly to ADP - in cytosol

what is oxidative level phosphorylation

removes electrons from organic compounds and posses through series of electron acceptors to molecules of oxygen - in inner mitochondrial membrane

what are the steps of glycolysis

*occurs in cytosol

1. glucose enters cell

2. one glucose molecule oxidised to TWO pyruvate molecules (2 NADH, 4 ATP)

3. oxygen → aerobic respiration = convert to acetyl coenzyme A into Krebs cycle, no oxygen → anaerobic respiration

4. pyruvic acid enters mitochondrion and converted to acetyl coenzyme A

5. acetyl-CoA enters Krebs cycle

6. Krebs cycle is an 8-enzyme-catalysed reaction in mitochondrial matrix, carries NADH, FADH2 and CO2, not much ATP

7. glycolysis produced 2 of 3 carbon molecules called pyruvate (6C)

explain the process of pyruvate with NO oxygen

anaerobic respiration

• oxidation of NADH and FADH2

• produce less energy than aerobic respiration

• oxygen is NOT the terminal acceptor

• requires another electron to replace O2

why does pyruvate need to be converted into acetyl-CoA with oxygen

• must be converted to acetyl-CoA in mitochondrial matrix

• oxidation of NAD+ to NADH

• acetyl-CoA has 2 carbon units needed for citric acid cycle

explain the processes in the citric acid/krebs cycle

• in mitochondrial matrix

• oxidises acetyl-CoA

• releases CO2 and transfers NADH and FADH2

what happens to the electrons in the citric acid cycle

• electrons removed during citric acid cycle

• carried by NADH and FADH2

explain the electron transport chain process

1. NADH and FADH2 formed during aerobic respiration are high energy electron carriers

2. NADH molecules carry into inner mitochondrial membrane where electron transfer their electrons to membrane associated proteins

3. proton gradient formed from membrane protein protons are pumped into mitochondrial space

4. protons diffuse through ATP synthase during formation of ATP form ADP and phosphate = chemiosmosis

explain the process of chemiosmosis

ADP + Phosphate = ATP

oxidative phosphorylation

process where energy stored in electrochemical proton gradient to synthesise ATP

explain the difference between anaerobic respiration vs aerobic respiration

anaerobic respiration → small amount of energy produced

aerobic respiration allows ATP generation when mitochondrial oxidative metabolism cannot meet immediate energy demand during exercise

what are the main roles of the urinary system

1. water and ion balance → adjusts and control volume of water loss in urine as well as Na+, K+ and Cl-

2. excretion → metabolites, foreign chemicals

3. regulation of blood pressure → Na+ balance, RAAS

4. regulation of red blood cell production

5. regulation of vitamin D activity

what are nephrons and what is the function

functional unit of kidney

filters blood plasma and form urine

what parts make up the nephrons

1. renal corpuscle

• glomerulus → filters plasma into renal capsule

• renal capsule → collects the instial filtrate

2. renal tubule

• proximal convoluted tubule → reabsorbs useful organic nutrients from the filtrate

• nephrons loop → reabsorbs more than 90% of water from filtrate

• distal convoluted tubule → secrete wastes products

• drains into collecting duct

what are the structures of the renal system

1. kidneys

• filtres blood

• regulate fluid and electrolyte balance

• produce urine

2. urinary tract

• maintains chemical balance of salts, water, acid base levels in the blood

3. uretes

• transports urine from kidneys to bladder

4. urethra

• carries urine from the bladder to the external environment

5. urinary bladder

• temporarily stores urine

what are the blood vessels in the nephron and function

• afferent arterioles → bring blood into glomerulus

• glomerulus → fenestrated capillaries drives filtration of water and small solutes into bowman’s space

• efferent arterioles → carries blood away from glomerulus

• peritubular capillaries → surround renal tubules and recieve reabsorbed water and solutes

what does the proximal convoluted tubule reabsorb and secrete

reabsorb:

• filtered water

• Na+

• site of tubular reabsorption

secrete:

• H+

• organic acids

what does the nephron loop reabsorb and secrete

ascending loop reabsorb

• Na+

• Cl- move from tubule

• impermeable to water

ascending loop secrete

• N/a

Descending loop reabsorb

• permeable to water

descending loop secrete

• minimal

what does the distal convoluted tubule reabsorb and secrete

reabsorb

• secretion of ions acids, drugs and toxins

• Na+

• Cl-

• Ca2+

secretion

• K+

• H+

what does the collecting duct reabsorb and secrete

reabsorb

• water under ADH control

• Na+ under aldosterone

secretion

• K+

• H+

what is the importance of fluid for homeostasis

maintains blood volume and normal cell size

what is the importance of electrolyte for homeostasis

maintains fluid balance and support nerve and muscle function

what is the importance of acid-base for homeostasis

maintains arterial blood pH, allows proteins and enzyme to function properly

what is the difference between ICF and ECF

ICF

• fluid inside cell

• high in K+

• phosphate

• negatively charged proteins

ECF

• fluid outside cell

• high in Na+

• Cl-

• HCO3

what are the key hormones of the renal system and the function

ADH→ increases water reabsorption by the kidneys

aldosterone → increases Na+ reabsorption, increases K+ secretion in DCT/collecting duct

angiotensin II → supports blood pressure, increase Na+ and H2O conservation, increase Na+ and H2O excretion

what is renal thereshold

the plasma concentration at which a substance first begins to appear in the urine

• above threshold = substance can be fully reabsorbed

• below threshold = transporters become saturated, excess remains in filtrate and excreted

explain the process of the movement of water

• water moves between ECF and ICF across cell membrane

• via osmosis

• moves towards higher solute concentration

how does the renal system gain fluid and losses regulation

• kidney filters large volume of fluid from blood

• water reabsorbed from the nephron back into circulation

• amount of water reabsorbed adjusted according to body’s needs

• ADH increases water reabsorption in collecting duct

explain what happens if the body is dehydrated

• water loss increases ECF osmolarity

• water moves from ICF to ECF

• osmoreceptors detect increased ECF osmolarity

• ADH increases

• kidneys conserve water by producing more concentrated urine

explain the importance of electrolyte balance

• must remain in appropriate range

• depends on intake, absorption, distribution and excretion

• kidneys plays a role in electrolyte balance

• hormones help adjust renal absorption and secretion

what is the importance of Na+ in electrolyte balance

ECF cation

• determines ECF osmolarity

• regulated ECF volume = influences blood volume and BP

• filtered by kidneys

• aldosterone increase Na+

• ANP promotes Na+ excretion

what is the importance of K+ in electrolyte balance

• establish membrane potential

• ECF changes ECF potassium concentration affect nerve and muscle activity

• kidneys regulate K+ excretion

• aldosterone increase K+ secretion in distal nephron

what is the importance of Cl- in electrolyte balance

• osmotic balance and electrical neutrality

• linked with Na+ and H2O

• kidneys regulate Cl- reabsorption and excretion

• contributes to acid base regulation

what is the importance of Ca+ in electrolyte balance

regulation:

• bones acts as a major reservoir

• kidneys regulate Ca2+ reabsorption and excretion

• PTH increases blood calcium levels

• calcitriol increases intestinal calcium absorption

what is the importance of Mg2+ in electrolyte balance

• enzyme activity

• supports normal nerve and muscle function

• cellular energy processes

• kidneys regulate Mg2+ reabsorption and excretion

what is the importance of P (phosphate) in electrolyte balance

• ATP

• contributes to bone structure

• ICF buffering system

• kidneys regulate phosphate excretion, PTH promotes this

what are chemical buffers

• resist sudden changes in pH

• binding and releasing H+

• work in both ECF and ICF

• do NOT REMOVE underlying acid/base from body

what are respiratory buffers

• CO2 produced during cellular respiration

• lungs remove CO2 via ventilation

• increased ventilation = increased CO2 removal

• decreased ventilation = decreased CO2 retained

• changes in CO2 affect buffer system and pH

what are renal buffers

• kidneys secrete H+ into tubular fluid

• reabsorb filtered bicarbonate

• excrete urinary buffers (phosphate)

• slower than respiratory

what is the level of pH regulation in regards to the type of buffers, response time and role

• chemical buffers = immediate = limit sudden pH changes

• respiratory regulation buffers = minutes = adjusts CO2 removal

• kidney (renal regulation) buffers = hours to days = adjusts H+ excretion and bicarbonate handling

what happens during acidosis

• body more acidic

• lowers pH

• respiratory: CO2 increases

• metabolic: bicarbonate decreases, acid increases

what happens during alkalosis

• more alkaline

• raises pH

• respiratory: CO2 decreases

• metabolic: bicarbonate increases, acid is lost

function of male reproductive system

• produce haploid spermatozoa

• deliver spermatozoa into uterus and fallopian tube

what are the components of the male reproductive system

1. testes

2. epididymis

3. ductus deferns

4. urethra

5. seminal glands

6. prostate gland

7. bulbourethral gland

8. penis

9. scrotum

function of testes

produce spermatozoa

function of epididymis

maturation and storage of spermatozoa

function of ductus deferens

stores spermatozoa

conduit for spermatozoa delivery

function of urethra

passageway for urine from bladder, sperm from ejaculatory duct

function of seminal glands

secretes largest quantity fluid for semes production, duct drains into ductus deferens

function of prostate gland

produces prostatic fluid

function of bulbourethral gland

mucous secreting gland

function of penis

release of urine and semes

function of scrotum

sac containing testes, body temp regulation

what is the male reproductive cycle

1. spermatozoa production (spermatogenesis)

2. sperm maturation, sperm moves through epididymis

3. sexual erection - parasympathetic activity

4. emission - sympathetic activity

5. ejaculation

6. hormonal maintenance

what is spermatogenesis

• meiosis I and II occurs

• production of sperm starts at outermost layer of seminiferous tubule walls

• proceeds towatds lumen

what is the purpose of nurse cells

• maintenance of blood-testies barrier

• supports mitosis and meiosis

• supports spermiogenesis

• secretion of inhibin

• secretion of androgen-binding proteins

• secretes mullerron-inhibiting factor

hormones of male reproductive system

testosterone

• from synthesised cholestrol in leyding cells

• controls growth, development and maintenance of sex organs

• final maturation of sprem

• stimulates descent of testies

function of female reproductive system

• produce haploid ova

• produce environment for fertilisation and development of ova

• expel offspring

• provide nutrition for offspring

what are the components of the female reproductive system

1. ovaries

2. fallopian tubes

3. uterus

4. vagina

5. external gentitlia

6. mammary gland

function of ovaries

• production of oocyte

• oocytes grow and mature in folliclues until ovulation

• held by mesovarium and ligaments

function of fallopian tubes

• transports and nourishment of oocyte

function of uterus

• mechanical protection, nutritional support and waste removal for embryo

• contraction during childbirth to eject foetus

layers

1. perimetriym

2. myometrium

3. endometrium

function of vagina

• eliminates menstrual fluid

• holds spermatozoa after sexual intercourse

• final portion of birth canal

function of external gentitlia

• greater vestibular gland → secretes lubricating fluid onto surface during sexual intercourse

• paraurethral glands→ secrete at the opening of urethra

function of mammary gland

• lactation for infant

• oxytocin and prolactin

what are the hormones of the female reproductive system

• GnRH = triggers release of LH and FSH

• LH and FSH = trigger production of estrogen, progesterone and androgen

• Estrogen and progesterone = sex hormones

• inhibin = decrease the release of LH and FSH, main sex hormone

explain the ovarian cycle

1. GnRH stimulates FSH and LH secretion

2. FSH and LH stimulate follicle to grow, mature and secrete sex hormones

3. negative feedback inhibits inhibin and estrogen levels

4. sudden rise of estrogen = short positive feedback stimulate LH and FSH (ovulation)

5. progesterone level will rise and take over estrogen and corpus luteum

6. no pregnancy occurs, corpus luteum degrades hormone levels drop

explain the menstrual cycle

1. menstrual phase

• uterus sheds all but deepest part of the endometrium

• hormones are low

2. proliferative phase

• functional layer of the endometrium is rebuilt under estrogens

• ovulation occurs at end of this phase

3. secretory

• 14 days endometrium prepares for an embryo implant under rising levels of progesterone from corpus luteum

• no fertilisation then corpus luteum degenerates and hormone levels drop, deprives endometrium, oxygen and nutrient begins to menses

functions of common contraception

• combined oral contraceptive pill

• minute doses of estrogen and progesterone

  • slows hypothalamic pituitary action

  • negative feedback decrease GnHR release

  • inhibin follicular development and prevents ovulation

  • increases cervical mucus to inhibit sperm

explain what menapause is

• cessation of ovulation and menstruation

• fluctuaing and decreasing levles of hormones

  • decrease estrogen and progesterone concentration

  • increased contraception of GnRH, FSH and LH levels

explain the process of fertilisation

1. Oocyte & spermatozoo forms zygote

2. Becomes a uploid cell, & start to divide

3. Triggers meiosis Il to complete & second polar body removed

4. Sperm & Ovum nuclei joining

5. Fertilisation activates the formation of the blastomere → morula →
   blastocyst

6. blastocyst formed on day 5/6

7. forrmation of pre embryo

explain the embryo developmental stages

1. fertilisation

• oocyte and spermatozoa forms zygote

• cell division and migration makes blastocyst

2. implantation

3. gastrulation

• ectoderm

• mesoderm

• endoderm

4. placentation

5. embryogenesis

what are the functions of the placenta

• allow for communication and nutrient/oxygen movement from mum to baby

• gas exchange - O2 and CO2

• nutrient transfer

• waste removal

• hormone production

• immune production

hormones involved in fertilisation

hCG → similar to LH, keeps corpus luteum funcitonal for 3-4 months

progesterone and estrogen

• maintains endometrial lining to prevent menses

• corpus luteum produces until placenta takes over

• estrogen production increases towards end of 3rd trimester

hPL and placental prolactin

• prepares mammary gland for milk production

relaxin

• increases pubic flexibility for expansion

• inhibits uterine contractions by delaying oxytocin release

• cause cervix during delivery

explain the germ layers

1. ectoderm

• interacts with external environment and builds nervous system

2. mesoderm

• provides structural support, movement, internal transport

3. endoderm

• forms epithelial linings and major glands

explain the process of foetal circulation

1. Ductus venous - venous shunt that bypasses the liver

2. Foramen ovale - opening the intestinal septa to bypass pulmonary circulation

Ductus arteriosus - transfers blood from the pulmonay trunk to aortic trunk

when lung expands circulation changes in alteration to blood pressure and flow

what are the mechanisms of labour

1. dilation

• onset of labour

• cervix dilates and water breaks

2. expulsion

• foetus pushed through fully dialted cervix (!0cm) from viganial canal

3. placental

• tearing of placenta from endometrium and ejection out of the uterus

• muscle tension

explain mechanism of lactation

• breast milk or infant

• milk production = prolactin

• milk let down = oxytocin