Tissues 2 Flashcards
Describe the difference between exocrine and endocrine glands in terms of what they do and how they are made
Exocrine glands secrete into tubes (sweat, salivary) and endocrine glands secrete into the blood. To make them columnar epithelium and stem cells proliferate down from the base. For exocrine glands this then forms the lining for a tube and for endocrine the group detaches and surrounds red blood cells.
What different structures can exocrine glands have?
They can have tubular (shaped like a tube) or acinar (shaped like a grape). These are simple but they can also be compound which is tubuloacinar.
Name two exocrine glands and what they secrete
Mucous glands have secretions rich in proteoglycans and the secretion plus water gives mucous. Serous glands have a protein rich secretion.
What are myoepithelial cells?
They are epithelial cells turned into muscle cells to contract and help release excretions. They are still classed as epithelial cells because they’re still attached to the basement membrane.
Describe the epithelial components of the liver
The parenchyma includes hepatocytes arranged in rows/cords between blood vessels. They have multiple functions including secretion. The support epithelial cells line the blood vessels and bike ducts.
Describe the epithelial components of the kidneys
The parenchyma are epithelial cells organised into nephrons. They have multiple functions including filtration of blood, partial absorption if filtrate and overall to release urine from the kidney. The support epithelial cells line the blood vessels and the renal pelvis which receives toxic urine.
Describe some abnormal functions of epithelial cells and give some examples of diseases which involve this
Over/under proliferation
Over/under secretion
Loss of cilia/ciliary beat
The pituitary gland can be abnormal in that it can produce too much or too little growth hormone (pituitary gigantism/dwarfism)
In the uterine tube the mucous glands can function abnormally when chlamydia trachomatis is prevalent. This produces a thick mucus so the sperm/ovum gets trapped and the patient is infertile.
Name types of connective tosses
Blood/bone marrow Mucous Reticular Loose Dense-regular or irregular Cartilage Bone Adipose
What is the connective tissue in adipose?
Mesentric fat is the attachment point and delivery point for the gut.
There is adipose in bone marrow.
What are the three connective tissues in the ECM?
Fibres- rope like (collagen and elastin)
Ground substance-jelly like (proteoglycans, hyaluronic acid, glycoproteins)
Tissue fluid
Describe the structure and formation of collagen
It is inelastic but flexible with a great tensile strength. There are 19+ types.
It is formed from a fibroblast which turns into a triple stranded helix then collagen fibril and collagen fibre.
(When a tendon is damaged the collagen is only repaired to the collagen fibril)
Describe elastic fibres and their structure
They’re made out of the protein elastin and can stretch 1.5 times their resting length and return to their original shape. They have microfibrils and amorphous component. They’re generally found in sheets rather than fibres and they’re yellow in colour (aorta).
Name some components of loose connective tissue
Fibroblasts Macrophages Adipocytes Mast cells Undifferentiated mesenchyme cells These are permanent (fixed) cells. White blood cells (transient cells)
Give examples of dense connective tissue
Regular dense- tendon
Irregular dense-sebaceous gland(skin)
Name some abnormal functions of connective tissue
Leukaemia (blood/bone marrow)
Loss/abnormal fibres called epidermolysis bullosa (loose/dense)
Tear of the cartilage
Osteoporosis/petrosis (bone)
