Gland structure and function Flashcards
State the definition of a gland
An aggregate of epithelial cells that are specialised for the secretion of a substance
State the function of gland
Regulate human physiology by receiving stimulus from the brain, the circulating levels of chemicals and neighbouring cells
How many types of glands are there and briefly describe the glands and provide examples for each type
- Endocrine gland
- secrete directly into blood
- secretions are hormone
- Eg; Pituitary gland, Thyroid gland, Parathyroid gland - Exocrine gland
- secrete into a location or region of the body through a duct
- secretions are enzymes, lubricants, mucous, serous, proteins
- Eg; Salivary gland, sweat glands, sebaceous glands,
Name the hormones secreted by the Anterior Pituitary Gland and state their functions
- ACTH, LH, FSH, TSH : regulate most glands of the endocrine system
- Prolactin : Stimulates milk production in mothers
- Somatotrophin : Regulates growth of body tissues
Name the hormones secreted by the Posterior Pituitary Gland and state their functions
- ADH : prevent water loss from kidney
2. Oxytocin : signals uterus for delivery in pregnant women
Name the hormones secreted by the Thyroid and Parathyroid glands and state their functions
Thyroid :
- T3 and T4 : controls metabolism
- calcitonin : calcium homeostasis
Parathyroid :
- Parathyroid hormone : calcium homeostasis
Name the hormones secreted by some exocrine glands and state their functions
- Salivary gland :
- secrete saliva for partial digestion of food - Sweat gland :
- secrete sweat to regulate body temp - Sebaceous gland :
- secrete sebum on skin and in ear to protect tissues from pathogens
What is canalicularisation and where does this occur?
It is when the central cells die off to produce duct. Occurs in the formation of exocrine gland
Where is angiogenic factors produced and state its functions
- Produced in endocrine gland
- Stimulate blood vessel growth in and around epithelial cells
Describe the formation of glands
- Growth signal received
- Proliferation of cells and their downgrowth into subjacent connective tissue occur
If exocrine gland;
3. Central cells die off to produce duct through canalicularisation
If endocrine gland;
3. angiogenic factors produced to stimulate blood vessel growth in and around epithelial cells
How does branching of glands occur?
- Immature fibroblasts release basic FGF10
- Epithelial cells move towards signal
- Tubule elongation occur if Growth factor 1 active
- Tubule branching occur if Growth factor 2 active
How many types of epithelial cells are there in exocrine glands and state their functions
- 2 types
- Cells lining the ducts
- Cells that make secretory products
State the different shapes of gland ducts and give and example for each
- Simple tubular : Intestinal gland
- Simple branched tubular : gastric gland
- Simple alveolar : -
- Simple branched alveolar : sebacceous glands
- Compound tubular : duodenal gland
- Compound alveolar : mammary gland
- Compound tubuloalveolar : salivary gland
What are the types of secretions by exocrine gland?
Mucous and Serous
Describe the growth and development of salivary gland
Prebud - Initial bud - Pseudoglandular - Canalicular - Terminal Bud
Describe the growth and development of the breast
- same process as salivary gland
- stops until puberty
- at puberty, ovaries produce oestrogen and progesterone which restarts breast development
- at pregnancy, prolactin production stimulates creast secretion
State the classifications of glands based on mode of secretion and briefly explain each function with examples
- Merocrine Gland
- fusion of vesicles with apical membrane
- eg; endocrine gland of pancreas - Apocrine Gland
- partial loss of cytoplasm
- eg; - Holocrine Gland
- complete loss of cytoplasm or cell
- eg; sebaceous gland in skin
What are the pathways for Merocrine secretion?
- Regulated Secretions
- secretory granules accumulate in large vesicles and released by exocytosis upon stimulation
- needs Ca2+ to work - Constitutive Secretions
- secretory granules packaged into small vesicles
- continuously released to cell surface
Define Glycosylation
The covalent attachment of sugars by enzyme to proteins and lipids to form glycoproteins and glycolipids
Describe the role of Glycosylation
- Prevent protein and lipid digested by intracellular protein
- Cell recognition
- aid protein folding
Define Exocytosis and Endocytosis
- secretion of molecules outside cell via vesicle fusing to membrane
- engulfing of molecules inside cell via vesicle formation
Define Phagocytosis and Pinocytosis
- process where cells engulf other cells
- process where cells ingest liquid droplets
What are the types of glandular control?
- Humoral stimulus
- Neural stimulus
- Hormonal stimulus
