Session 5: Glands 2 and connective tissues proper Flashcards
Describe the difference between simple and compound
Simple: single layer of cells
Compounds: multiple layers of cells, seen by several layers of nuclease
Describe the difference between acinar and tubular
Acinar: alveolar shape seein in exocrine glands( which have ducts), releases mucus
Tubular: tube-like shaped glands
Describe between serous and mucous
Serous cells secrete enyzmes( which stain darker as they contain proteins)
Mucous cells secrete mucus which dont stain, so looks clear
What is the function of a goblet cell(unicellular gland) in the jejunum and colon?
Produces and maintains layer of mucin- a glycoprotein which offers a procetive mucus blanker over small intestine layer. Mucin proteins then produce mucus which helps movement of substances with cilia.
What is the function of parotid glands?
Major salivary glands below and in front of each ear, on left side of head, produces salva for digestion and lubrication
What is the function of submandibular glands?
Lubricates and moisturizes mouth and throat. Aids in digestion- breaks down food with moisture and enzymes.
Function of liver
Secretes bile which is stored in gall bladder- which emulsifies fat. Alcohol detoxification, excretion of bilrubin etc.
Explain the location and function of myoepithelial cells in relation to eocrine gland secretion
Some of the cells at the secretory ends of ducts change into myoepithelial cells- cells that have features of both a smooth muscle cells and an epithelial cell. Helps to eject( squeeze) secretions from the duct.
How are mumps formed?
Viral infections causes parotid glands to swell, leads to intense pain. Treatment: abcess drainage or surgery. Swelling of this gland could also occur due to blockage due to bacterial infection- solved with antibiotics.
Difference between parasympathetic and sympathetic secretion
Parasympathetic: large volume of watery, enzyme rich saliva
Sympathetic: small volume, thick, mucus rich saliva
Note that salivary secretion is neural
What occurs in the liver lobule?
Deoxygenated blood from hepatic vein and oxygenated blood from hepatic artery mix in the liver accinus and comes into contact with the wall of hepatocytes( which have membrane transport). Large molecules enter through fennestrated endothelial cells, other go back through hepatic vein.
Describe a Kupffer cell and its function
Type of macrophage in sinusoidal lining. Traps and destroys erythroycytes after 120 days- similar to role of spleen. Migrates into site when there is inflammation or damage in liver.
Describe the role of stellate cells in liver failure
Stellate/Ito cells undergo transformation when liver is damaged to form myofibroblasts and collagen which leads scar formation at site. Sinusoids loose fenestrations, and this leads to liver fibrosis.
What do hepatocytes contain?
Peroxisomes( contains oxidising agents), free ribosomes, RER, SER, golgi apparatus, glycogen deposits. Lots of regeneration power- up to 50% damage can be repaired in 8 days.
What does the liver store?
Iron, copper, lipid soluble vitamins A,D,E,K, and glucose
List some anabolic and catabolic functions of the liver
Anabolic: Produces albumin, amino acids
Catabolic: Poisons/ alcohol, hormones( insulin/glucagon)
Define connective tisue
Joins together other tissues, supports body and its structures to provide protection for its underlying organs. Consists of extracellular matrix( ground substance and fibres) and cells( like fibroblasts and adipocytes)
Cite examples of connective tissues and explain their functions
Tissue binding and support: fibroblasts, important in wound healing process, formation of scars
Protection: Macrophage, antigen presenting cells, presents foreign substances to T cell to be destroyed
Fuel storage: Adipocytes
Transport of substances: Mast cells, release large ammounts of inflammatory mediators when inflammation occurs.
Describe the function of extracellular matrix and its components
Extracellular matrix is the network of ground substance and fibres
Ground substance: gelatinus material consisting of glycoproteins, lipids and water
Collagen fibres:flexible with high tensile strength
Recticular: spongy, provides supporting framework, absent in areolar tissue
Elastic fibres: allows tissues to recoil after stretch or distension
What is the difference between loose and tense connective tissue? In terms of components and tissue function
Loose connective tissue: few cells, low collagen, high ground substance, thin, more variety of cells. Function: attaches epithelial tissues to underlying tissue
Regular dense connective tissue: many cells, high collagen, low ground substance, thick, less variety of cells. Function: links bones together at joints
What is the difference between loose and tense connective tissue? In terms of components and tissue function
Loose connective tissue: few cells, low collagen, high ground substance, thin, more variety of cells. Function: attaches epithelial tissues to underlying tissue
Regular dense connective tissue: many cells, high collagen, low ground substance, thick, less variety of cells. Function: links bones together at joints
Classify different types of loose and dense connective tissue
Loose: fascia, a connective tissue and has 3 types- Superficial, deep and visceral. Fascia is made up of fibrous connective tissue and is flexible and can resist unidirectional tension
Dense: 2 types- regular and irregular. Irregular: contains collagen 1 fibres in all directions, can resist stress in all directions. Example: deep layer of dermis, submucosa of intestine. Regular: collagen 1 fibres parallel, can only resist stress in 1 direction. Example: tendons, ligaments.
Dense is harder to cut through than loose.
Function of irregular dense connective tissue
Non-parallel collagen 1 fibre bundles resists forces in multiple directions to prevent tearing. Skin can return to original form after it is bent.
Describe the structure and function of the areolar tissue
It is a loose connective tissue- therefore consists of extracellular matric( ground substance and fibres) and different types of cells. It holds vessels that supply fluids, acts as packaging around organs and is involved in inflammation pathways( mosq bite)- it has the facility to swell and expand, then return to original size
Describe the structure and function of mucoid connective tissue
Shapeless, loose connective tissue only found in umbilical cord. Contains 2 arteries and a vein. Arteries carry deoygenated fetal blood to the placents while vein carries oxygenated blood to fetus.
Describe the structure and function of adipocytes
Consist of multiple small lipid droplets with nuclues, cytoplasm, and organelles all squeezed to centre of cell in brown adipocytes. Function: provides insulation and energy reserve
White vs brown adipose tissue
White: single lipid droplet, normal mitochondria count, peripheral nucleus. In adults- slow breakdown and heat only generated after shivering induced.
Brown: multiple lipid droplets, increased number of mitochondria, central nucleus. In neonates and young children- faster lipid breakdown, oxidative phosphorylation is uncoupled to produce heat. Calories generated can double.
Describe the structure and function of elastic fibre in lungs
Very fine fibres that surround alveoli of lungs. In COPD, these fibres are irreversibly destroyed- leads to exhaling difficulties when individual is under stressful conditions
Describe the structure and function of recticular fibres in lymph nodes
They are fine branching threads made of collagen type 3. Usually arranged in network and attached to collagen 4. Forms major organ structure of lymphoid tissues and liver.
What happens to lymph nodes during an infection
Antigen presenting cells show antigens in blood stream to lymphocytes at lymph nodes. Lymphocytes respond by proliferating, which leads to swelling in neck, shoulder, armpits and groin.
Explain the causes, mechanism, signs and symptoms of scurvy
Vitamin C deficiency leads to scurvy, a condition that involves poor wound healing and impaired bone formation. This is due to the synthesis of abnormal collagen that lacks its usal strength
Explain the causes, mechanism, signs and symptoms of Marfan’s syndrome
Caused by mutations in the fibrillin 1 gene and elastic tissue is abnormal. Leads to tisse irregularities like long bones. At risk of aortic rupture, and a span greater than their height.
Explain the causes, mechanism, signs and symptoms of osteogeneis imperfecta
‘Brittle bone disease’: due to mutated colleagen fibres that dont knit together or insufficient amount produced. Results in weakened bones, presence of blue sclera(outside pupil area), hearing loss, loose joints, flat feet, poor teeth development
