A&P II Final Exam Flash Cards

Scrotum

A pouch of skin and subcutaneous tissue that holds the testes outside the body to maintain a temperature 2-3°C below body temp, which is optimal for sperm production.

Testes

Produce sperm and testosterone. Spermatogonia form sperm, Sertoli (nurse) cells nourish them, and Leydig cells produce testosterone.

Leydig cells

Produce testosterone and are found between seminiferous tubules.

Sertoli cells

Support and nourish developing sperm within the tubules.

Spermatogenesis progression

Spermatogonia → primary spermatocytes → secondary spermatocytes → spermatids → spermatozoa. Sperm are released into the tubule lumen but cannot swim until maturation in the epididymis.

Structure of a sperm

Head: Nucleus with 23 chromosomes; Acrosome: Enzymes for egg penetration; Neck: Centrioles; Middle piece: Mitochondria for ATP; Tail: Principal & end piece for movement.

GnRH

From hypothalamus, stimulates LH/FSH.

LH

Stimulates testosterone from Leydig cells.

FSH

Stimulates spermatogenesis via Sertoli cells.

Testosterone

Promotes male traits and sperm production.

Effects of testosterone

Supports male prenatal development, secondary sex traits, sexual function, anabolism, and is regulated by negative feedback.

Epididymis

Curved organ on the testis; stores and matures sperm over ~14 days.

Ductus deferens

Connects epididymis to urethra; transports sperm during ejaculation.

Spermatic cord

A bundle of structures (ductus deferens, vessels, nerves, cremaster muscle) that passes through the inguinal canal from the scrotum to the abdomen.

Male urethra

Parts include prostatic urethra (in prostate), membranous urethra, and spongy (penile) urethra; carries semen and urine.

Male accessory sex glands

Seminal vesicles: Secrete alkaline fluid with fructose; Prostate: Milky, acidic fluid with enzymes; Bulbourethral glands: Alkaline mucus to neutralize urine and lubricate.

Erectile tissues of the penis

2 corpora cavernosa and 1 corpus spongiosum; fill with blood via parasympathetic innervation, causing erection. Ejaculation is sympathetic-driven.

Oogenesis

Begins before birth and results in one ovum and polar bodies, while spermatogenesis starts at puberty and produces four sperm per precursor cell.

Follicles

Located in the ovaries, contain developing oocytes, and secrete estrogen and inhibin.

Female reproductive hormones

GnRH: Stimulates FSH and LH release; FSH: Stimulates follicle growth; LH: Triggers ovulation and corpus luteum formation; Estrogen: Promotes follicle growth, secondary sex traits; Inhibin: Inhibits FSH; Progesterone: Maintains uterine lining.

FSH

Promotes follicle growth

Dominant Follicle

One follicle becomes dominant and secretes estrogen & inhibin

Estrogen

Increases GnRH and triggers LH surge

LH

Triggers ovulation

Corpus Luteum (CL)

Forms after ovulation and produces progesterone

hCG

Embryo-produced hormone that rescues CL to maintain progesterone and pregnancy

Female Meiosis

Produces only one ovum because most cytoplasm goes to one secondary oocyte, while other daughter cells become polar bodies and degenerate

Infundibulum

Funnel-shaped part of the oviduct that captures oocyte

Fimbriae

Finger-like projections aiding in the capture of the oocyte

Ampulla

Longest part of the oviduct; site of fertilization

Isthmus

Narrow section of the oviduct joining the uterus

Perimetrium

Outer serosa layer of the uterus

Myometrium

Muscular middle layer of the uterus

Endometrium

Inner layer of the uterus; functional layer is shed monthly

CL Degeneration

Occurs if pregnancy does not happen, leading to decreased progesterone

Menstruation

Process where the functional endometrial layer is shed

Fertilization

The fusion of a sperm and secondary oocyte to form a diploid zygote

Zona Pellucida Penetration

Sperm penetrate by releasing enzymes from the acrosome that digest a pathway through the zona pellucida

Polyspermy Prevention

A cortical reaction alters the zona pellucida after one sperm penetrates, blocking others from entering

Zygote

A single diploid cell formed by the union of sperm and egg

Morula

A solid ball of cells resulting from cleavage of the zygote

Blastocyst

A hollow ball of cells that implants into the uterine wall

Chorion

An outer membrane of the embryo that contributes to placenta formation

Germ Layers

Ectoderm (nervous system, skin), Mesoderm (muscles, bones, circulatory system), Endoderm (digestive and respiratory linings)

Induction

The process by which one group of embryonic cells influences the development of another group

Neural Tube Formation

Formed by folding of the ectoderm; it becomes the brain and spinal cord

Developing Brain Parts

Forebrain, midbrain, hindbrain

Placentation

Occurs when the chorion (fetus) and endometrium (mother) form the placenta, allowing nutrient and waste diffusion

Placenta Functions

Gas/nutrient exchange, waste removal, hormone production (e.g., hCG, progesterone)

Embryonic Period

Fertilization to 8 weeks

Fetal Period

9 weeks to birth

Teratogen

Any agent that causes birth defects; examples include alcohol, drugs, infections (e.g., rubella)

Gene

A segment of DNA coding for a protein or trait

Allele

Different versions of a gene

Homozygous

Two identical alleles

Heterozygous

Two different alleles

Genotype

Genetic makeup

Phenotype

Observable traits

Punnett Square

Place parent alleles along rows and columns, fill in combinations to find probabilities (e.g., 25%, 50%).

X and Y Chromosomes

X is larger and carries more genes; Y determines male sex and carries fewer genes.

Sex-linked Inheritance

Traits carried on X or Y chromosomes; X-linked traits more often affect males due to having only one X.

RAA Pathway

The Renin-Angiotensin-Aldosterone pathway regulates blood pressure and fluid balance. Renin → angiotensin I → angiotensin II → aldosterone → increases sodium and water retention.

Key Reproductive Hormones

GnRH (from hypothalamus), LH and FSH (from anterior pituitary), estrogen, progesterone, testosterone.

Hemoglobin's Function

To bind and transport oxygen in red blood cells.

Erythropoiesis

Red blood cell production, stimulated by erythropoietin (EPO) from the kidneys in response to low oxygen levels.

Path of RBC

Vena cava → Right atrium → Right AV valve → Right ventricle → Pulmonary valve → Pulmonary arteries → Lungs (Gas exchange) → Pulmonary veins → Left atrium → Left AV valve → Left ventricle → Aortic valve → Aorta → Systemic Capillaries → Back to vena cava.

Differences Between Arteries and Veins

Arteries: Thicker walls, higher pressure, no valves; Veins: Thinner walls, lower pressure, have valves.

B and T Cells Development

B cells: Develop in bone marrow; produce antibodies; T cells: Mature in thymus; kill infected or abnormal cells.

Cell-mediated Immunity

T cells attack infected cells.

Antibody-mediated Immunity

B cells secrete antibodies to target pathogens.

Inhalation

Diaphragm contracts → pressure decreases → air in.

Exhalation

Diaphragm relaxes → pressure increases → air out.

Tidal Volume

The amount of air moved in or out during a normal breath.

Vital Capacity

The maximum amount of air a person can exhale after a full inhalation.

Pancreas Exocrine Function

Produces digestive enzymes and bicarbonate to neutralize stomach acid.

Functions of the Liver

Metabolism, detoxification, bile production, and storage of nutrients.

Digestion and Absorption Location

Most digestion and absorption occur in the small intestine (especially the jejunum).

Glycolysis

Glucose is broken down into two pyruvic acids, producing 2 ATP.

Krebs Cycle

Acetyl-CoA is broken down to produce CO₂, NADH, FADH₂, and ATP.

Electron Transport Chain

Electrons from NADH and FADH₂ generate ATP through oxidative phosphorylation.

Excess Nutrients

Excess carbs, proteins, or lipids are all converted into triglycerides and stored in the adipose tissue.

Parts of the Nephron

Glomerulus: Filtration; PCT: Reabsorption; Loop of Henle: Concentrates urine; DCT: Secretion; Collecting duct: Final water reabsorption.

Urine Formation Steps

Filtration (glomerulus); Reabsorption (PCT, loop); Secretion (DCT).

ADH Effect on Kidney

Increases water reabsorption in the collecting duct by inserting aquaporins.