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

Immune system = hemopoietic Functions: Production of immune cells (and rbc) Immune defense

Organs Central: Central: red bone marrow, thymus peripheral: peripheral: lymph nodes, tonsils, spleen

LYMPHOID SYSTEM I cvl A R U o Tonsils of Waldeyer’s Ring Spleen Solitary nodules Peyer’s patch V Appendix Lymph nodes - cervical, axillary, inguinal, mesenteric, etc Lymphocyte circulation via blood vessels and lymphatics T Primary lymphoid organs - Marrow M & Thymus T Secondary organs M

Red Bone Marrow Functions: 1. formation of all blood cells, except T-lymphocytes Functions: 1. formation of all blood cells, except T-lymphocytes 2. contains CFU – blood stem cell 2. contains CFU – blood stem cell Structure: -- basic – reticular tissue, -- sinuses (wide capillaries), -- sinuses (wide capillaries), -- cords of hemopoietic cells -- cords of hemopoietic cells

Thymus Functions: Functions: 1. production of T-lymphocytes independent 1. production of T-lymphocytes independent /they become antigendependent /they become antigendependent in the peripheral organs/ in the peripheral organs/ 2. production of hormones (thymopoietin, thymosins) 2. production of hormones (thymopoietin, thymosins) to promote development and action of T lymphocytes to promote development and action of T lymphocytes

Thymus Capsule gives off trabeculae, divide parenchyma into lobules with cortex and medulla Capsule gives off trabeculae, divide parenchyma into lobules with cortex and medulla Reticular epithelial cells – basis of lobules Reticular epithelial cells – basis of lobules secrete hormones secrete hormones Very large in fetus; after age 14 begins Very large in fetus; after age 14 begins aging involution aging involution in elderly mostly fatty and fibrous tissue in elderly mostly fatty and fibrous tissue

Histology of Thymus

THYMUS young Cortex - dark Medulla - light Lobules Connective tissue Hassall’s thymic corpuscle round, red, flattened epithelial cells. Their amount increases with age Packed lymphocytes (thymocytes)

Lymph Node Functions: production of B-lymphocytes, Functions: production of B-lymphocytes, filtration of lymph flows through sinuses filtration of lymph flows through sinuses STRUCTURE: STRUCTURE: Cortex contains lymphatic nodules with stroma (reticular CT) and lymphocytes Cortex contains lymphatic nodules with stroma (reticular CT) and lymphocytes Paracortical zone contains T-lympocytes Paracortical zone contains T-lympocytes Medulla consists of medullary cords of plasmocytes – lymphocytes, producing antigens Medulla consists of medullary cords of plasmocytes – lymphocytes, producing antigens

Basic are reticular cells = macrophages phagocytize foreign matter Basic are reticular cells = macrophages phagocytize foreign matter lymphocytes respond to antigens lymphocytes respond to antigens lymphatic nodules contain germinal centers lymphatic nodules contain germinal centers for B cells activation for B cells activation

Lymph Node Fig a and b Sinuses for lymph flow

Lymph Node

Tonsils Functions: 1. production of B- lymphocytes, 2. immune defense Functions: 1. production of B- lymphocytes, 2. immune defense

Tonsils Location – folds of mucous membrane of the oral and pharyngeal cavities Location – folds of mucous membrane of the oral and pharyngeal cavities Multiple groups of large lymphatic nodules Multiple groups of large lymphatic nodules Palatine tonsils Palatine tonsils Pharyngeal tonsil Pharyngeal tonsil Lingual tonsils Lingual tonsils

Tonsil Covered by stratified epithelium Covered by stratified epithelium Pathogens get into tonsillar crypts and encounter lymphocytes Pathogens get into tonsillar crypts and encounter lymphocytes

Spleen Parenchyma contains: Parenchyma contains: red pulp: sinuses filled with erythrocytes red pulp: sinuses filled with erythrocytes white pulp = lymphatic nodules: lymphocytes, macrophages; surrounds small branches of splenic artery white pulp = lymphatic nodules: lymphocytes, macrophages; surrounds small branches of splenic artery Functions Functions B-lymphocytes production B-lymphocytes production blood storage blood storage RBC distruction RBC distruction immune reactions: filters blood, detects antigens immune reactions: filters blood, detects antigens

Spleen

Lymph Nodules in the GIT - PROTECTION

Endocrine System is the second regulating system

Produces hormones to the blood Produces hormones to the blood Regulates growth, metabolism Regulates growth, metabolism

Classification CENTRAL organs : hypothalamus, hypophysis, epiphysis CENTRAL organs : hypothalamus, hypophysis, epiphysis PERIFERAL : thyroid, parathyroid, PERIFERAL : thyroid, parathyroid, adrenal glands.

In some organs the endocrine tissue constitutes part of them : the pancreas, the pancreas, the ovaries and the testes. the ovaries and the testes.

Individual endocrine cells are found in a variety of organs, e.g. the GIT and the kidneys.

Hypothalamus Part of the CNS Part of the CNS Contains Nuclei of neurosecretory cells Contains Nuclei of neurosecretory cells anterior(1) anterior(1) intermediate(2), intermediate(2), posterior(3) posterior(3)

H.-1 Supraoptic nucleus produces vasopressin (antidiuretic hormone – ADH) increases reabsorbtion of water in kidney. Supraoptic nucleus produces vasopressin (antidiuretic hormone – ADH) increases reabsorbtion of water in kidney. Paraventricular nucleus produces oxytocin - contraction of muscle of the uterus during parturition Paraventricular nucleus produces oxytocin - contraction of muscle of the uterus during parturition

H.-2 Releasing factors - liberins (stimulate) and statins (inhibit) for tropic hormones of the adenohypophysis Releasing factors - liberins (stimulate) and statins (inhibit) for tropic hormones of the adenohypophysis

HypothalamusHypophysis 32 1

H.-3 contains nerve cells, innervating endocrine glands contains nerve cells, innervating endocrine glands

(Hypophysis) Pituitary Gland The pituitary gland is attached to the brain by the infundibulum 1 The pituitary gland is attached to the brain by the infundibulum 1 locates under the hypothalamus locates under the hypothalamus

Pituitary Gland 2 Parts:  neurohypophysis  adenohypophysis (d.- pars distalis, i. - pars intermedia). i. - pars intermedia). n a id

Pars distalis  acidophil cells  basophil cells.

Acidophils cells  1. somatotrophs (produce growth hormone (GH or somatotropin)  2. mammotrophs secrete prolactin (LH).

Basophil cells  1. Thyrotrophs  1. Thyrotrophs produce thyroid stimulating hormone (TSH or thyrotropin).

Basophil cells  2. Gonadotrophs  2. Gonadotrophs produce   follicle stimulating hormone (FSH) regulates ovogenesis, spermatogenesis   luteinizing hormone (LH) stimulates production of testosterone by Leydig cells in males, formation of corpus luteum in females.

Basophil cells  3. Corticotrophs  3. Corticotrophs secrete adrenocorticotropic hormone (ACTH)

Pars intermedia Pars intermedia produces melanocytostimulating hormone and produces melanocytostimulating hormone and lipotropic hormone lipotropic hormone

Neurohypophysis Cells are pituicytes Cells are pituicytes Hering’s bodies – ends of axons, contain hormones of hypothalamus Hering’s bodies – ends of axons, contain hormones of hypothalamus

Development Neurohypophysis develops from the floor of third brain ventricle. Neurohypophysis develops from the floor of third brain ventricle. Adenohypophysis develops from an ectodermal diverticulum - Rathke’s pouch, that grows upwards from the roof of the stomatodaeum. Adenohypophysis develops from an ectodermal diverticulum - Rathke’s pouch, that grows upwards from the roof of the stomatodaeum.

Epiphysis or PINEAL BODY

contains two basic types of the cells: 1 – pinealocytes; 1 – pinealocytes; 2 – interstitial cells (glial cells) 2 – interstitial cells (glial cells)

Epiphysis or PINEAL BODY controls all cyclic processes in human organism

Hormones of the thyroid gland thyroxin, or tetraiodothyronin, T4, thyroxin, or tetraiodothyronin, T4, triidothyronin – T3, triidothyronin – T3, calcitonin calcitonin

and T3 regulate carbohydrate, lipid T4 and T3 regulate carbohydrate, lipid and protein metabolism calcitonin lowers blood calcium level calcitonin lowers blood calcium level

consists of follicles, consists of follicles, lined by cuboidal epithelium lined by cuboidal epithelium The follicle cavity is filled with colloid = thyroglobulin – complex of hormones The follicle cavity is filled with colloid = thyroglobulin – complex of hormones

Between follicles there are parafollicular cells Between follicles there are parafollicular cells (or C-cells), (or C-cells), produce calcitonin

TSH of hypophysis stimulates T3,T4 production!

PARATHYROID GLAND chief or principal cells and chief or principal cells and oxyphil cells. oxyphil cells.

Its Parathormone (PTH) increases the blood calcium level by stimulating bone resorption Its Parathormone (PTH) increases the blood calcium level by stimulating bone resorption is not under control of hypophysis is not under control of hypophysis

ADRENAL (suprarenal) GLANDS consist of : an outer cortex and an inner medulla

 Cortex- epithelial cords:  zona glomerulosa  zona fasciculata  zona reticularis  Medulla

Hormones:  zona glomerulosa -- mineralocorticoids – Na,Ca homeostasis and water balance  zona fasciculata - glucocorticoids – carbohydrate metabolism  zona reticularis - sex hormones

zona fasciculata and zona reticularis are under control of ACTH of hypophysis zona fasciculata and zona reticularis are under control of ACTH of hypophysis

Medulla Consists of sympathetic neurons – chromaffin cells Consists of sympathetic neurons – chromaffin cells produse: produse: adrenaline and adrenaline and noradrenaline noradrenaline -- stress hormones -- stress hormones