Glands By Dr. Berlina - PowerPoint Presentation

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Glands

By

Dr.

Berlina

Terrence Mary

Assistant professor

Dept of Anatomy

Glands

Some epithelial cells may be

specialised

to perform a

secretory

function. Such cells present singly or in groups, constitute glands.

Based on structure--- unicellular,

multicellular

Unicellular are interspersed among other epithelial cells.

Eg

. Lining the intestines.

Multicellular

- develop as

diverticulae

from epithelial surface.

Exocrine glands or externally secreting

glands – put their secretions into an epithelial surface, directly or through ducts.

Endocrine glands or internally secreting gland or ductless gland-glands lose all contact with the epithelial surface from which they develop, they pour their secretions into blood.

Simple gland – when all the

secretory

cells of an exocrine gland discharge into one duct.

Compound gland – no. of group of

secretory

cells, each group discharging into its own duct. These duct unite to form larger duct that ultimately drain into an epithelial surface.

Both (simple & compound) the secreting cells may be arranged:

a) Tubular –tube may be straight, coiled or branched

b) Acini – cells may form rounded sacs

c) Alveoli –flask shaped structures

Exocrine gland may be

Unicellular

Simple tubular

Simple alveolar or acini

Compound tubular

Compound

alveolai

Compound

tubulo

alveolai

Classification based on the nature of their secretion

Mucous gland – secretion contain

mucopolysaccharides

. Secretion collects in the

glial

parts of the cells. As a result nuclei are pushed to the base of cell & they flattened

Protein secreting cells

Mucin

secreting cells

Steroid producing cells

Serous gland- protein in nature, nuclei are centrally placed.

Classification – basis of manner in which

their secretion are poured out of cells

Merocrine

or

eccrine

/

epicrine

- secretions thrown out of cells by the process of

exocytosis

, the cell remaining intact .

Apocrine

– apical parts of the cells are shed off to discharge the secretion.

Eg

. Atypical sweat glands, mammary gland.

Holocrine

– entire cells disintegrates while discharge its secretion.

Eg

. Sebaceous gland

Glands divided into lobes

Intralobular – lying with in the lobule.

Interlobular –lying in the interval between lobules .

Interlobar

– lying between adjacent lobes

Exocrine gland - rich

bloood

supply, their activity is under nervous or hormonal control

Endocrine gland – rich network of blood, capillaries or

sinisoids

.

Neoplasm can arise from the epithelial

linning

of gland.

Adenoma – benign growth arising in a gland.

Adenocarcinmoma

- malignant growth.