Kharkov National Medical University Department of Histology, cytology and embryology LECTURE for dentistry students

The Urinary System I.Kidneys II. Ureters III. Bladder IV. Urethra

Excretion –of wastes from body fluids Regulation of –blood volume and pressure –plasma ion concentrations +Conserving nutrients Functions of the urinary system

Outer cortex and inner medulla –The cortex is composed of 1.25 million nephrons – structural and functional units Structure of the kidneys

Figure 26.4a, b The Structure of the Kidney

Filtration of blood Reabsorption of organic nutrients, water and ions Secretion of waste products into tubular fluid Nephron functions include:

Nephron consists of: 1. renal corpuscle 2. PCT – proximal convoluted tubule 3. loop of Henle 4. DCT – distal … Collecting tubule receives urine

1. Renal Corpuscle – filtration of blood Consists of: A. Bowman’s capsule with parietal and visceral layers and

B. Glomerulus of capillaries Blood is filtrated because of big pressure due to: afferent arteriole brings blood to capillaries is twice bigger, then efferent arteriole, taking blood from capillaries Glomerulus

1. Renal Corpuscle B. Bowman’s capsule 1. visceral layer consists of podocytes with processes

1. Renal Corpuscle Processes interdigitate around glomerular capillaries. The narrow space between processes is the filtration slit.

FILTRATION BARRIER: 1. Endothelium of capillary (fenestry) 2. Basal lamina - 3 layers 3. Podocytes (slits) Through barrier pass wastes, water, small proteins, sugar, salts 150 litres of primary urine per day - by filtration 1.5 litres of urine per day - by reabsorption

2. Proximal Convoluted Tubule Reabsorption : simple cuboidal epithelium with brush border longest tube

2. Proximal Convoluted Tubule 1. brush border = microvilli

2. Proximal Convoluted Tubule reabsorption of: a. all glucose b. amino acids c. ~85% NaCl & H 2 0 b. protein secretion/excretion

3. Loop of Henle 1. forming hypertonic urine 2. is almoust impermeable to water

4. Distal Convoluted Tubule 1. simple cuboidal epithelium 2. cells smaller than PCT 3. lack brush border

4. Distal Convoluted Tubule Functions under influence of aldosterone 2. absorbs Na+ (and H 2 O) 3. secretes K +, H +, NH4 ++

Urine Production 3 process involved in urine production –All of these processes occur in the Nephrons of the kidneys –Glomerular filtration –Tubular Reabsorption –Tubular excretion and secretion

All nephrons enter to Collecting Tubules Under ADH (vasopressin) reabsorps H 2 O

Collecting Tubules continue to calyces and pelvis

Juxtaglomerular apparatus a. Juxtaglomerular cells - modified smooth muscle of afferent arteriole synthesize renin effect: increase Na + and Cl - absorption – distal tubules

b. macula densa of DCT - cells columnar, able to sense ionic concentration. c. polkissen cells, additional renin secretion

Blood Flow A.Renal artery B.Interlobar arteries C. Arcuate arteries D. Interlobular arteries

Ureter & Bladder A. Ureter 1. mucosa a. transitional epithelium b. lamina propria 2. muscularis a. inner longitudinal b. outer circular 3. adventitia

Male reproductive system :

Functions: Reproductive --- production of spermatozoa Endocrine --- production of male sex hormone (testosterone)

Testis Septae – divide on lobules Lobule contains seminiferous tubules

The Convoluted Seminiferous Tubules Consists of two types of cells: spermatogenic cells Sertoli cells

provide mechanical support for the spermatogenic cells and nutrition

Spermatogenic cells Spermatogonia – Primary spermatocytes Secondary spermatocytes Spermatids Spermatozoa

Spermatogenesis From spermatogonia (stem cells) by meiosis and spermiogenesis form spermatozoa

The Convoluted Seminiferous Tubules

Interstitial tissue Leydig cells lie in between the convoluted seminiferous tubules, secrete testosterone

epididymis contains a long, highly coiled ductus for storage of sperms continues to the vas deferens vas deferens

the accessory sex glands - the seminal vesicles the formation of the sperm coagulum and regulation of sperm motility the prostrate liquefies the semen the bulbourethral glands - secret mucous

HORMONAL REGULATION

Female Reproductive System

Ovary contains Follicles for production of ovum and estrogen Folliculardevelopment consists of stages Ovarian follicles

follicles: follicles: Primordial Primordial Primary Primary unilaminarunilaminar multilaminarmultilaminar -1. estrogen Secondary follicle Secondary follicle Tertiary - Graaffian Tertiary - Graaffian

-estrogen (stroma) (in antrum)

Ovarian Follicles - oogenesis ovulation corpus luteum

The Corpus luteum - Yellow body Is formed after ovulation (rupture of follicle)Is formed after ovulation (rupture of follicle) theca interna cells and granulosa cells start accumulate lutein. theca interna cells and granulosa cells start accumulate lutein. and begin to produceand begin to produce 2. progesterone2. progesterone

The Corpus luteum 1. of menstruation – functions within 14 days after ovulation if the oocyte is not fertilized, then degenerates into a corpus albicans - whitish scar tissue in the ovaries.1. of menstruation – functions within 14 days after ovulation if the oocyte is not fertilized, then degenerates into a corpus albicans - whitish scar tissue in the ovaries. 2. of pregnancy - functions for 2-3 months after ovulation if fertilization occurs.2. of pregnancy - functions for 2-3 months after ovulation if fertilization occurs.

corpus albicans = degenerative corpus luteum

The Oviduct The oviduct functions as a conduit for the oocyte, from the ovaries to the uterus.The oviduct functions as a conduit for the oocyte, from the ovaries to the uterus.

The Oviduct consists of a mucosa, a muscularis and a serosa.consists of a mucosa, a muscularis and a serosa. epithelium resting on a lamina propria.epithelium resting on a lamina propria. The muscularis consists of an inner circular layer and an outer longitudinal layer.The muscularis consists of an inner circular layer and an outer longitudinal layer.

The Uterus The walls of the uterus are composed of a mucosal layer, the endometrium, and a fibromuscular layer, the myometrium. The peritoneal surface of the uterus is covered by a serosa - perimetrium.The walls of the uterus are composed of a mucosal layer, the endometrium, and a fibromuscular layer, the myometrium. The peritoneal surface of the uterus is covered by a serosa - perimetrium.

The cyclic change of endometrium is called the menstrual cycle (28 days). It happens under hormons of ovary There are three phases:There are three phases: Menstrual - desquamation phase.Menstrual - desquamation phase. Postmenstrual or proliferative phase (or follicular),Postmenstrual or proliferative phase (or follicular), Premenstrual or secretory phase (or luteal),Premenstrual or secretory phase (or luteal), Only the stratum functionalis of mucosa takes part in the menstrual cycle.

Mammary gland The mammary glands are modified glands of the skin.The mammary glands are modified glands of the skin. They are compound branched alveolar glands, which consist of lobes separated by dense interlobar connective tissue and fat.They are compound branched alveolar glands, which consist of lobes separated by dense interlobar connective tissue and fat.

Active mammary gland: duct & secretory cells

Placenta consists of a fetal portion, formed by chorion and a maternal portion, formed by decidua basalis of uterus.