Exocrine And Endocrine Glands Flashcards
What are glands?
Epithelial cells that produce secretions
(Ectodermal origin)
What do endocrine glands do?
Do they have ducts?
Produce hormones
No ducts
Where do secretions (hormones) pass out of the endocrine glands?
Pass out into the interstitial tissue then into blood capillaries scattered within tissues of these glands
What type of secretions do exocrine glands produce and what do they secrete?
Mucous secretions and they secrete many different substances
Where do exocrine glands ducts release their secretions?
Lumen or onto surfaces of organs
Some are enzymes and some saliva
What are endocrine glands?
Part of epithelial surface (lining of digestive tract)
Or separate organs such as thyroid/ pituitary gland
What do endocrine hormone secretions do?
Regulate bodily functions
Maintain homeostasis
Name the 3 patterns of hormone secretion in endocrine glands?
Chronic
Acute
Episodic
What is chronic pattern of secretion like in endocrine glands?
Regular increases or decreases throughout the day
(Thyroxin)
What is acute pattern of secretion like in endocrine glands?
Amount secreted depends on stimulus
Ie. Some stimuli may cause secretion of large amounts (stressed)
While other stimuli may result in less hormones being secreted
(Adrenaline of cortisol)
What is episodic pattern of secretion like in endocrine glands?
Episodes of hormones produced and episodes of no production
Eg. Growth hormone
Insulin = increased secretion after eating
Name the 3 types of regulation of hormone secretion in endocrine glands ?
Humoral secretion
Neutral regulation
Hormonal regulation
Describe Humoral regulation in endocrine glands.
Prescience of blood borne molecules
Eg. High glucose levels stimulates insulin secretion
Describe neutral regulation in endocrine glands.
Neuron stimulates hormone production
Eg. Sympathetic nervous system (fight or flight) stimulates epinephrine release.
Describe hormonal regulation in endocrine glands.
Hormone secretion stimulus another hormone to be secreted
Eg. Hormones from pituitary gland stimulates tested to make testosterone
Give 3 classes of hormones?
Proteins and polypeptides
Steroids
Derivative of amino acid tyrosine
Describe proteins and polypeptides type of hormone.
Secreted by pancreas and parathyroid gland
Stored within cell and released on demand
Eg. Pancreas, parathyroid gland
Describe steroid type of hormone.
Synthesised from cholesterol
Released directly into circulation
Can’t be stored
Eg. Adrenal cortex, ovaries, placenta
Describe derivative of amino acid tyrosine type of hormone.
Secreted by the adrenal medulla and thyroid
Where is the thyroid gland located and what is it formed of?
Location in midline of neck in front of trachea
Formed from 2 parts joined together by central isthmus
How many parathyroid glands are there?
Where are they located?
What are they separated by?
4
Corners of thyroid gland
Separated from thyroid by layer of fibrous tissue
Structure of parathyroid glands?
Single layer of cuboidal epithelium
Contain colloid
Increase in size (columnar) when active
Structure of thyroid glands?
- what is main bulk made up of?
- what is follicular epithelium?
- what do follicles store?
Main bulk made up of follicles
Single layer of cuboidal epithelium that lines thyroid glands
Collied that is secreted by the follicular epithelial
What does colloid contain?
Thyroxine T4
Tri-iodothyronine T3 (active hormone)
What is 10% of thyroid gland made up of?
What is the structure of this?
Where is it found?
C cell
(Parafollicular cell)
Has clear cytoplasm
Present within interstitial tissues surrounding follicles
What do C cells produce?
Calcitonin
- hormone that regulates calcium
What do chief cells produce and what is it important for?
Parathyroid hormone important for calcium metabolism
How many chief cells are there and where are they found?
4
1 in each corner of thyroid gland
What does the parathyroid hormone act on?
Osteoclasts (large multi nucleated cells responsible for bone resorption)
Shat happens when calcium and other mineral levels decrease?
Parathyroid glands secrete hormone which activates the osteoclasts to break down bone
Minerals are released into the body which bring the levels up to within normal range.
Secretion stops
What does Hyperparathyroidism result in?
Increased activity/ size of parathyroid glands (benign tumours or hyperplasia
This results in increased hormone secretion, bone resorption and calcium level.
What effect does Hyperparathyroidism have on bone?
Bone shows soft tissue lesions developing within the mineralised tissue.
Jaw/skull bones and skeletal system also affected
What are the 3 most important calcium metabolisms?
Calcitonin
Parathyroid hormone
Vitamin D
What 2 cells populations are the parathyroid glands composed of?
Chief cells
Ocyphill cells
What is an ocyphill cell?
Present in clusters
Larger but less number than chief cells
Cytoplasm as granular as there’s lots of mitochondria
Exact function = unknown
Function of chief cells?
Synthesise and secrete parathyroid hormone
Describe exocrine gland secretions
Released through ducts that open onto epithelial cells or directly to surface
What is a unicellular gland?
Gland made up if 1 cell only
Eg. Goblet cell
2 arrangements of multicellular glands?
Secretory sheets = arranged in sheets as part of other organ
Pockets - gland cells set back from epithelial surface
Are majority of exocrine glands unicellular or multicellular?
Multicellular
Name 5 simple multicellular glands?
Simple tubular
Simple branched tubular
Slime cooler tubular
Simple acinar
Single branched acinar
Name 3 compound multicellular list glands?
Compound tubular
Compound acinar
Compound tubuliacinar
Describe the merocrine gland.
Substance produced stored in vesicles
When need vesicles move up and substance is released only the duct
- salivary
Describe the apocrine gland.
Substances produced stored within cell
When needed moves up into apical part of the cell
Top part (containing product) seperste from rest of cell
Drops off into duct and travels through it into surface
- mamory gland
Describe the Holocrine gland.
Entire cells drops off into duct with product and it’s secreted to surface
Replacement cell is formed
- cervacious gland
What are serous secretions?
Watery secretions containing enzymes
Protein rich secretion
What are mucous secretions?
Contain mucins which hydrate to form mucous
Thicker
Contain water and microproteins
What is a mixed secretion?
Mixture of both serous and mucous
What are the 3 pairs of salivary glands?
Where are they found?
What type of secretions do they produce?
Parotid (in front of ear) - serous secretion
Submandibular - both secretion
Sublingual (under tongue) - mucous secretion
Describe features of mucous acini.
Cuboidal/ columnar in shape
Contain mucus
Nuclei are flat and pushed to bottom of cell
Have ducts
Describe features of serous acini.
Round
Nuclei not as flat and near bottom of cell
Contain granuals
Enzymes and proteins that enter into secretions
What types of secretions in pancreas?
Endocrine = 2%
Exocrine = majority
Name substances found in pancreas.
Islets of langerhans
Insulin
Alpha cells producing glucagon
Delta cells (nuclei)
F cells producing pancreatic polypeptide
What is found in exocrine proportion of pancreas
Lipase
Amylase
Proteinases
Name 2 diseases of the pancreas.
Pancreatic cancer
Diabetes myellitus
What is the difference between type 1 and type 2 diabetes?
Describe similarity.
- Insulin dependent
- Insulin resistant
Both have effect on most systems in body.
Describe type 1 diabetes.
Insulin dependent
Destruction of beta cells
5-10% of all people with diabetes
Describe type 2 diabetes.
Insulin resistant
Tissues lose their sensitivity to insulin so it becomes ineffective
3 oral effects of diabetes.
Periodontitis
Dry mouth
Susceptibility to infections
What is periodontitis?
Inflammation of tissue that holds teeth (periodontal ligament)
Factors affecting periodontitis?
Lack of response of immune cells to bacteria or changes to blood vessels and blood reaching area
What does dry mouth lead to?
Low saliva secretion therefor more susceptible to fungal infections (thrush)
What is hypofunction of endocrine system?
What does it lead to?
Reduced hormone secretion
Autoimmune diseases
Infections
What is hyperfunction of endocrine system?
What does it lead to?
Excessive hormone release
Results in tumour
What is diabetes mellitus in endocrine system?
Hormone resistance
Autoimmune condition
Body is resistant to insulin
What can cause changes in endocrine system?
Pregnancy
Menopause
Stress
Obesity
