Antatomy II final

Scrotum

loose skin and subQ tissue supporting the testes outside the pelvic cavity

Testes in scotum

because sperm production tequires a temperature about 2-3 degrees C below body temp

Testes produce

sperm and testosterone

site of sperm production is seminiferous tubules

leydig cells

produce testosterone

Sertoli cells

provide nourishment and protection for developing sperm

Spermatogenesis

1. spermatogonia (diploid stem cells) differentiate into diploid primary spermatocytes

2. primary spermatocytes undergo meiosis I to secondary spermatocytes (haploid)

3. meiosis II to become spermatids

4. spermatids develop into sperm

primary spermatocytes, secondary spermatocytes, spermatids, sperm

sperm

Head, nucleus with 23 condensed chromosomes and acrosome caplike vesicle with enzymes that allow the sperm to penetrate an oocyte

Tail:

neck, constricted region behind head, contains centrioles

middle piece, mitochondria arranged in a spiral providing energy for locomotion

principal piece, longest portion

end piece, tapered

gonadotropin releasing hormone

stimulates cells in the anterior pituitary gland to produce LH and FSH

Effects of testosterone

prenatal development

development of male secondary sex characteristics

development of sexual function

stimulation of anabolism

Epididymis

located in testes, site of sperm maturation

Ductus Deferens

connects the epididymis to the urethra

travels through spermatic cord, sperm travel through the ductus deferens

Spermatic cord

consists of the ductus deferens, testicular artery, veins draining the testes, autonomic nerves, lymphatic vessels, and the cremaster muscle

ascends out of the scrotum

Urethra

• Shared by reproductive and urinary systems 

• Semen and urine passes through

accessory sex glands

• Seminal vesicles, secretes an alkaline, viscous fluid containing fructose, prostaglandins and clotting proteins 

• Prostate, secretes milky, slightly acidic fluid containing citric acid, proteolytic enzymes, acid phosphate, and seminalplasmin 

• Bulbourethral glands, secrete alkaline fluid during sexual arousal that neutralizes acids from urine and mucus for lubrication

erectile tissues

• Large amounts of blood enter the tissue into dilated blood sinuses 

• Erectile tissues of the penis are arterioles 

Oogenesis vs spermatogenesis

• Spermatogenesis begin at puberty but oogenesis begins in utero 

• Females are born with all the oocytes they will ever have

Follicles

Follicles are little sacs that contain oocytes, they produce estrogen and inhibin

Estrogen

 increases libido and stimulation of GnRH release from the hypothalamus

Inhibin

 inhibits the release of FSH from the pituitary

Progesterone

• prepares and maintains a quiet, happy endometrium for implantation of a fertilized ovum and inhibits release of GnRH and LH, preventing cycling

saving the CL

• FSH stimulates development of several primordial follicles 

• One of the follicles emerges as the dominant follicle and grows larger, producing estrogen and inhibin 

• The increased GnRH and inhibition of FSH causes a spike in LH

• LH stimulates ovulation 

• After ovulation a corpus luteum develops 

• Corpus Luteum produces progesterone 

• The corpus luteum has a 2 week lifespan, but if pregnancy occurs, the embryo produces human chorionic gonadotropin (hCG), which rescues the CL

Polar bodies

After primary oocyte completes meiosis I, producing a haploid secondary oocyte (with the majority of the cytoplasm) and a haploid first polar body (essentially discarded nuclear material)

infundibulum

ends in a fringe of finger like projections called frimbriae

ampulla

widest and longest section (site of fertilization)

isthmus

short and narrow section

Perimetrium

outermost layer of uterine wall

myometrium

middle layer of uterine wall

endometrium

inner layer of uterine wall

Menstruation

• The uterus produces prostaglandin F2(alpha) which causes luteolysis, destruction of the corpus luteum 

• Decrease in progesterone from the degrading CL causes the sloughing of the uterine lining (menstruation)

fertilization

• Merging of the genetic information from haploid sperm and haploid secondary oocyte

sperm penetration

• Glycoproteins in the Zona Pellucida act as a sperm receptor 

• Sperm binding to the receptor triggers the acrosomal reaction, wherein the acrosomal enzymes are released to digest a path through the zona pellucida as the sperm’s lashing tail pushes it onward 

polyspermy prevention

The plasma membrane depolarizes, secretory vesicles from the oocyte undergo exocytosis, and the zona pellucida hardens

Zygote

when the haploid nucleus in the head of sperm and the haploid nucleus of fertilized ovum merge

Morula

16 cells that resemble a mulberry

Blastocyst

32 cells stage, the fluid now inside the morula rearranges the blastomeres into a large, fluid-filled blastocysts cavity

chorion

The extraembryonic mesoderm and trophoblast together form the chorion

3 germ layers

Endoderm, mesoderm, and ectoderm: a primitive streak establishes the head and tail ends of the embryo as well as the right and left 

• Cells of the epiblast move inward below the primitive streak and undergo invagination

Endoderm

epithelial lining of digestive canal, respiratory tract, and other organs

Mesoderm

muscles, bones, other connective tissues, and the peritoneum

Ectoderm

epidermis and nervous system

induction

The process whereby one tissue stimulates the development of an adjacent unspecialized tissue into a specialized one

neural tube

• When the neural folds approach each other they become the neural tube

• The neural tube develops into the brain and spinal cord

parts of the developing brain

primary brain vesicles

placentation

• Forming of the placenta occurs when the chorionic villi develop and project into the endometrial wall

• The fetal portion is formed by the chorionic villi of the chorion 

• The maternal portion is formed by the endometrium 

• Oxygen and nutrients diffuse from material blood to fetal blood and vice versa 

functions of the placenta

• Allows oxygen and nutrients to diffuse from maternal blood into fetal blood while carbon dioxide and wastes diffuse from fetal blood into maternal blood 

• Protective barrier as most microorganisms can’t pass through it (with the exception of certain viruses such as HIV, Polio, Measles)

• Stores nutrients (carbs, proteins, Ca, Fe) and releases them as needed 

• Produces hormones (progesterone, estrogen, hCG)

embryonic period

week 5 - 8

fetal period

week 9 - birth

teratogen

• Any agent or influence that is able to cause developmental defects in an embryo or fetus 

• Alcohol, Cigarette smoking, ionizing radiation (x-rays)

Gene

a unit of heredity transferred from a parent to offspring 

Allele

genes for the same trait that are in the same location on each homologue

homozygous

a person with the same alleles on homologous chromosomes (PP or pp)

Heterozygous

a person with different alleles on homologous chromosomes (Pp)

genotype

the actual genetic makeup relating to a trait

phenotype

the physical expression of the genotype

X and Y chromosomes

• Males have an X and a Y chromosome 

• Females have two X(s) 

sex-linked inheritance

When some recessive traits are much more commonly expressed in males than females Red-green color blindness (example)

RAA pathway

• Renin-angiotensin-aldosterone

  • Kidneys produce renin 

  • Renin converts angiotensinogen into angiotensin I

  • Angiotensin-converting enzyme (ACE) converts angiotensin I to angiotensin II

  • Angiotensin II stimulates aldosterone secretion

Follicle-stimulating hormone

• In women, stimulates production of follicles on ovaries 

• In men, stimulates production of sperm

Luteinizing hormone

• In women, cause ovulation 

• In men, production of testosterone

Hemoglobin’s function

A protein used to carry oxygen to all cells and to carry some carbon dioxide to the lungs

Erythropoiesis

• production of RBCs

• Erythropoietin, hormone that stimulates RBC production

RBC pathway

• Right atrium 

• Right atrioventricular valve 

• Right ventricle 

• Pulmonary valve 

• Pulmonary arteries 

• Pulmonary capillaries 

• Pulmonary veins 

• Left atrium 

• Left atrioventricular valve 

• Left ventricle 

• Aorta and systemic arteries 

Differences between arteries and veins

• Arteries carry blood away from heart, veins carry blood to the heart 

• Arteries have a layer of smooth muscle than veins 

• Arteries function under higher blood pressure 

• Veins have a one-way valve system 

B cells

• are made and mature in the red bone marrow

  •  Create antibodies 

T cells

• are made in red bone marrow and mature in thymus

  • Destroy harmful pathogens and send signals that control your immune system response to threats 

Cell mediated immunity

• Cells attacking cells 

• Intracellular pathogens 

Antibody mediated immunity

• Antibodies are specific for each pathogen, abs bind to the pathogen to mark it for destruction 

• Mostly for extracellular pathogens 

Inhalation

inspiration is caused by the diaphragm contracting 

Exhalation

expiration is passive unless forced by contracting internal intercostals and abdominal muscles. 

Tidal volume

 the amount of air moved in and out of the lungs with each normal breath

Vital capacity

maximum amount of air that can be moved in and out of the lungs (with maximal effort) 

pancreas produce

• Produces enzymes that digest carbs, proteins, fats, and nucleic acids

• and sodium bicarbonate (stomach buffer)

Functions of the liver

• Secretes bile

• Carb metabolism

• Lipid metabolism 

• Protein metabolism 

• Processing of drugs and hormones 

• Excretion of bilirubin 

• Synthesis of bile salts 

• Storage

• Phagocytosis 

• Activation of Vit. D

small intestine

majority of digestion and absorption occurs in

Glycolysis

a set of reactions in which one glucose molecule is oxidized, producing 2 pyruvic acid molecules (2 ATP and 2 NADH produced)

Krebs cycle

oxidation of acetyl CoA (2 ATP, 6 NADH, 2 FADH produced)

electron transport chain

Oxidation of NADH and FADH, transferring their electrons through a series of carriers (26 or 28 ATP produced)

Excess Carbs, Protein, or Lipids

Converted to glucose or triglycerides and stored as fat 

parts of the nephron

• Renal corpuscle

  • Glomerulus 

  • Glomerular capsule 

• Renal tubules 

  • Proximal convoluted tubule 

  • Nephron loop

  • Distal convoluted tubule 

Glomerular filtration

• at the glomerulus and glomerular capsule

  • Driven by blood pressure, water and small molecules move of the the glomerulus into the glomerular capsule 

  • Non specific

Tubular reabsorption

• proximal convoluted tubule

  • Much of filtrate is reabsorbed, especially water, glucose, amino acids, and ions

Tubular secretion

• distal convoluted tubule

  • Tubular cells actively secrete some substance back into the tubules to be excreted

  • K+, NH4+, creatinine, and certain drugs (penicillin) are also excreted

Affects of ADH

• ADH increases water reabsorption 

• Collecting ducts and distal convoluted tubules 

• Increase in the filtration rate of the juxtamedullary nephrons