Bio Final

urinary system functions

1. filters blood, regulates water, and electrolytes

2. acid-base balance

3. waste disposal

4. maintain blood pressure

5. EPO

6. convert Vitiman D into active form

urine formation

1. glomerular formation

2. tubular reabsorption

3. tubular secretion

1.glomerular filtration

water and solutes smaller than proteins are forced through the capillary walls and pores of the glomerular capsule into the renal tubes

2.tubular reabsorption

water, glucose, amino acids, and needed ions are transported out of the filtrate ion into the tubule cells and then enter the capillary blood

3. tubular secretion

H+, K+, creatine and drugs are removed from the peritubular blood and secreted by the tubule cells into the filtrate

glomerular filtration

• The affront arteriole delivers blood to the glomeruli

• glomerular capillaries covered in podocytes → root processes → filtration slits

• Blood pressure forces blood to be filtered through the capillaries

  • filtrate collected in glomerular capsule

  • filtrate: water, solutes(excluding proteins and RBC)

  • what isn’t filtered exits the glomerulus via efferent arteries

• filtrate next moves into the PCT

tubular reabsorption

• PCT cells are simple cuboidal epithelial cells w/ dense microvilli

  • absorptive function

  • passive and active transport process

• PCT cells reabsorbed the following from the filtrate

  • glucose, amino acids, water, ions

• transported from tubule cells into the peritubular capillaries

• nephron loop

• DCT

• cortical nephrons

• juxtamedullary nephrons

Tubular secretion

• substances sent from peritubular capillaries into the renal tube

• substances the body needs to excrete

  • H+, K+, creatine and drugs

urine formation

• what filtrate remains in the DCT moves on into the collecting duct

• water levels and the concentration of a few solutions are “fine tuned” by the cells of the collecting duct

• many nephrons share a single collecting duct

• collecting duct pours urine into the renal pelvis

urine constituents

nitrogenous waste

excess substances

unneeded substances

urine characteristics

• clear, pale to deep yellow

  • urochrome

  • color depends on concentration

• sterile

• slightly aromatic

• slightly acidic

• specific gravity of 1.001 to 1.035

thirst mechanisms

• stimulus

• osmoreceptors

  • hypothalamus

  • thirst center

• negative feedback

anti-diuretic hormone (ADH)

• produced in the hypothalamus, stored/ released by the posterior pituitary

• Prevents water loss through urination

• released when we are dehydrated

• target cells of the collecting ducts to increase water reabsorption

• diabetes insipidus: lack of ADH; Dilutes urine; intense thirst, severe dehydration

electron balance: Aldosterone

• aldosterone is produced by the adrenal cortex

• increases the reabsorption of sodium ions concentration in the DCT and collecting ducts

• NA+ and H+ are exchanged at the tubule transporters

• Cl- is reabsorbed with NA+

• water follows the salt, resulting in

  • increases blood volume

  • increased blood pressure

Acid base balance

• blood pH: 7.34-7.45

• alkalosis

• acidosis

• Mechanisms of pH balance

• respiratory mechanisms

• renal mechanisms

Mechanisms of pH balance

blood buffers

• prevents dramatic changes in H+ concentration ion

• bicarbonate buffer system (HCO2-)

respiratory mechanisms in acid base balance

elimination of CO2

renal mechanisms of acid base balance

excretion of HCO3-

reabsorption of HCO3-

male gonade’

testes

male gametes

sperm

female gonads

ovaries

female gametes

ova

diploid cell

the cell has two complete sets of chromosomes (1 from mom and 1 from dad)

Human diploid has 46 total chromosomes (23 from each parent)

haploid cell

the cell has one complete set of chromosomes (results from having meiosis); human haploid has 23 chromosomes (one single set)

mitosis

cell division is processed by somatic cells during growth, tissue/cell replacement, and wound healing

• cells duplicate their DNA and then divide into 2 daughter cells

• 1 single division occurs

• results in two identical daughters cells that are diploid

miTosis = Twins

meiosis

cell division process is used to create gametes (sperm and egg cells)

• The gamete (primary spermatocyte or oocyte undergoes 2 consecutive meiotic divisions resulting in 4 haploid cells

fertilization

haploid sperm and haploid egg combine during fertilization = diploid zygote → embryo

Meiosis is a reducing division

• before either process, the DNA must duplicate itself

• mitosis simply arranges and then splits its duplicated DNA, with 23 pairs going into each daughter cell. → The total is two daughter cells

• meiosis requires two divisions

  • 1st is to split the homologous chromosome pairs

  • 2nd is to split the duplicated DNA

  • total is 4 daughter cells

tail of a sperm function

provides for mobility

function if the midpiece

provides energy for mobility

head of the sperm function

provides genetic instructions and a means of penetrating the follicle cell capsule and oocyte membrane

steps of testosterones production

1. The hypothalamus releases gonadotropin-releasing hormone (GnRH)

2. GnRH stimulates the anterior pituitary to release gonadotropins- FSH and LH

3. FSH stimulates spermatogonia to produce sperm

4. LH stimulates the interstitial cells to release testosterone, which serves as the final trigger for spermatogenesis. Testosterone then enhances spermatogenesis

5. The rising level of testosterone exerts negative feedback control on the hypothalamus and pituitary

testosterone production

GnRH → FSH and LH

• FSH → spermiogenesis, germ cells

• LH → esosteron, Leydig cells

testosterone → spermatogensis, 2⁰ sex characteristics

ovary and oogenesis

• ovarian follicles

  • oocyte

  • follicle cells

• primary follicle

  • follicle growth, estrogen production

  • oocyte meiosis

• vesicular (Graafian) follicle

  • ovulation

• corpus luteum

  • progesterone production

Oogenesis, meiosis, and follicle development

Hormones: GnRH

FSH, LH

estrogen

progesterone

Uterine cycle

Hormones : GnRH

FSH, LH

estrogen

progesterone

pregnancy

• conception

• gestation period - aprox. 250 days

• embryo- up until 8 weeks post-fertilization

• fetus- week 9 until birth

fertilization

• ovum (ovulated secondary oocyte)

• sperm

• fertlization: fusion of material from egg and sperm

  • N+N=2N

  • zygote

ovum (ovulated secondary oocyte)

• viable ~12 - 24 hours

• in uterine tube

sperm

• viable (for fertilization) ~ 24-48 hrs

• chemotaxis (+ toward oocyte)

• Female reproductive tract: treacherous for sperm cells

• The acrosomal reaction x 1000s : hyaluronidase

• contact single sperm with oocyte membrane receptor

embryonic development

• cleavage

• implantation

  • timing

  • location

• HCG production

embryonic development

• gastrulation

• placenta

• umbilical cord

• extra-embryonic membrane

  • amnion

  • chorion