Glandular Tissue And Secretion Flashcards Preview

TOb > Glandular Tissue And Secretion > Flashcards

Flashcards in Glandular Tissue And Secretion Deck (34)
Loading flashcards...

Define gland

An epithelial cell specialised for secretion


Define exocrine gland

With duct


Define endocrine gland

Ductless, secrete directly into blood


Define merocrine secretion

By exocytosis
1) membrane bound compartment migrates to surface
2) fuses with membrane
3) contents released into extra cellular space


Define apocrine secretion

Non,embrace bound e.g. Lipid approaches surface
Makes contact and pushes up apical membrane
Thin layer of apical cytoplasm drapes around droplet
Membrane surrounding droplet pinches off from cell
Plasma membrane transiently smaller


Describe holocrine secretion

Disintegration of the cell
Release contents
Discharge of whole cell


Describe the mechanism of endocytosis

1) engulf material from outside cell
2) pinch off part of membrane to form a vesicle
3) membrane bound within the cell


How to endo and expcytosis allow trans epithelial transport?

Material endocytosed at one surface
Transport vesicles shuttles across cytoplasm via microtubules
Material exocytosed st opposite surface


Describe the structure of the golgi

Stack of disc shaped cisternae
One end of discs flattened, the other concave
Discs have swellings at edges


Describe function of the golgi

Transport tbrough sequential golgi cisternae
Packaging kf sorted contents through condensation
Glycosolation of proteins and lipids


Where is the destination of products from the golgi?

In secretory vesicles some retained in cell for jse e.g. Lysosome others enter plasma membrane (glycolyx)


Why is the golgi important?

Branching sugars offer complex shapes for specefic interactions
Destruction of this layer bu enzymes alters many specificity based properties of cells e.g. Adhesion, mobility, communication


Describe role of secretion in cell functions



Describe nervous control of secretion

Sympathetic nervous stimulation of adrenal medullary cells leads to release of adrenaline


Describe endocrine control of secretion

Adrenocorticotrophic hormone stimulates coretex of adrenal gland to release cortisol


Describe neuro-endocrine control of secretion

Nervous cells of hypothalamus control acth secretion from anterior pituatory


Describe negative feedback secretion control

Inhibitory effect of high t3/t4 levels on tsh synthesis in anterior pituatary


How are the majority of glands derivatives of epithelial tissues?

Were surface epithelia that have specialised to particular function, epithelial cells proliferate and leave surface to invade underlying connective tissue where basal lamina surrounds newly formed gland


What is the difference between endo and exocrine glands?

Exo into duct, endo into vascular (blood) or lymphatic system


What is the difference between simple and compund glands?

Simple dont branch, compound do


Describe the shape of acinar and tubular glands

Acinar - alveolar bubbles
Tubular - tube like


Describe the difference between serous and mucousal glands

Serous - watery secretionx free of mucus (enzymes)
Mucous - mucous rich mucins (dont stain well)


Describe goblet cells in jejunum

Goblet cells interspersed with simple columnar
Synthesise mucus and secrete it onto elithelial surface where it lubricates and acts as a protective barrier
Narrow stalk attaches swollen, mucous rich upper part if each goblet cell to basement membrane


Desfibe goblet cells large intestine

Crypts of liberkhun - simple tubular lined by water absorbative collumnar cells and mucus secreting goblet cells
As water is absorbed from gut mucus allows adherence of solid waste into a compact mass and also protects the epithelium from trauma


Describe the parotid gland

Serous exocrine
Below and infront of each ear inpairs
Adipose tissue develops with age
Septa radiate from the outer collagenous capsule subdividing the glandular tissue jnto lobules
Glandular tissue consists of serous acini and ducts
Saliva from parotid contains lots of salivary amylase and the antibody IgA which inactivates antigens in oral cavity
Capsule of collagen surrounds the whole gland
Saliva passes along striated duct


Describe the submandibular gland

Salivary gland either side of neck, below mandible
Compound tubuloacinar
Serous cells produce enzymes stored as zymohen


Explain the location of myoepithelial cells

Glandular epithelium above basement membrane
Sweat, mammary, lacrinal and salivary glands


Explain the function of myoepithelial cells

Contract in order to facilitate transport of luminal contents towards the duct


Describe the thyroid gland

In neck
Numrous follicles lined with simple cuboidal
Colloid within follicle is a glycoprotein complex called thyroglobulin which incorporates thyroid hormones before release
Numerous blood vessels form a fine reticular network between closely opposed follicles


Describe the parathyroid gland

Usually 4, ovoid, posterior wall of thyroid
Composed of masses and cords of epithelial cells supported by reticular fibres
Close association with capillary network
Oxyphil cells - unkown function
Chief cells- produce parathyroid hormones