Lecture 3: Connective Tissue Flashcards
Difference between epithelia and connective tissue
CT is not found on body surfaces, is vascular and has a large amount of extracellular material
3 purposes of connective tissues:
- Binds, supports and strengthens other body tissues.
- A major transport system of the body. (blood)
- A major site of stored energy reserves (adipose tissue)
Avascular Ct is an exception and includes both
cartiliage, tendons (vlittle)
similarity between Epithelia & CT
both have nerves
Connective Tissue is composed of
extracellular matrix and cells
ECM is made of 2 things
ground substance (the material between fibres and cells) + protein fibres
Ground substance is a mixture of
water, proteins, polysaccharides (GAGS)
The sugars in GS are called
Glycosaminoglycan (GAGs or mucopolysaccharides)
GAGS join with core proteins to form
proteoglycans
Glycosaminoglycans are long unbranched, repeating
disaccharide unit-(uronic sugar, amino sugar)
What is the important property of GAGS
they are highly polar, therefore attract water, trapping it so that GS is more jellylike.
Sulphated GAGs bind to proteins and includes
keratan, dermatan, herparin, chondroitin –sulphate
Non- sulphated GAG example
Hyaluronic acid
Hyaluronic acid is unusual as it doesn’t
covalently bond to core protein, instead is joined to various Proteoglycans.
Enzyme that breaks down in order to help the cell move- (sperm, white blood cell, bacteria)
Hyaluronidase ; makes GS more liquid
Disease states associated with ECM
abnormal periorbital ECM and thyroid disease
Name the 3 fibres in CT extracellular matrix: Thick to thin
Collagen, reticular and elastic
What are elastic fibres made of
the protein elastin surrounded by glycoprotein fibrillin
Marfan Syndrome happens because
mutation in chromosomes causes fibrillin to be made that can’t inhibit Transforming Growth factor beta.
What are reticular fibres made of and what makes them
collagen arranged in fine bundles with a coating of glycoprotein. made by fibroblasts
What is the function and location of adipocytes
store fat (triglycerides) and are found under skin and around organs (heart, kidney)
What is the function and location of fibroblasts
secrete components of the matrix (fibres and ground substance). They are the most numerous, and are found widely distributed, migrating through CT
What is the suffix of the immature cell class that will mature to cells with a suffix cyte
blast
What is the function and location of macrophages
they engulf bacteria and cell debris by phagocytosis. Phagocytic cells can either be fixed or wandering-> ready to gather at the site of infection. Come from monocytes.
What is the function and location of Plasma cells (from B lymphocytes)
they produce antibodies that attack foreign substances. Found in many CT sites (gut tract, resp. tract, salivary gland, red bone marrow)
What is the function and location of Mast cells
they produce histamine that dilate vessels as part of the inflammatory response. They are found alongside the blood vessels that supply connective tissue.
What is the function and location of Leukocytes
White blood cells (neutrophils, eosonphils) migrate out from blood to sites of infection to phagocytose microbes.
Embryonic connective tissues give rise to all other connective tissues. The two types are
Mesenchyme, mucous connective tissue
Mature connective tissues categories :
loose, dense, blood, lymph, cartilage, bone
Areolar CT is called the packing material of the body: what category is it, what is its structure, function and location
It is loose CT made from a random mix of the 3 fibres, cells in a semifluid GS. Its function is strength, elasticity and support. It is located around nearly every body structure-eg. subcutaneous layer of skin.
Adipose tissue: what category is it, what is its structure, function and location
It is loose CT made up of adipocytes. Its function is Insulation, Energy Source, Temperature control. Its found with areolar connective tissue.
Dense CT categories
regular, irregular, elastic
Dense Regular: what is its structure, function and location
(It looks like silk)
Structure is Regularly arranged collagen bundles with fibroblasts inbetween them. Provides strong attachment between various structures. Found in Tendons, Ligaments, aponeuroses (muscular system). Slow healing due to low blood supply.
What are the three types of cartilage
hyaline cartilage, fibrocartilage, elastic cartilage
Hyaline cartilage: what is its structure, function and location (bubbles)
Structure: prominent chondrocytes found in lacunae surrounded by perichondrium. provides smooth surfaces for movement . Found in the respiratory bones. ends of long bones.
What are the two types of bone tissue, their alias and position in bone
compact, aka cortical bone is the outer layer of bone and spongey aka cancellous bone is porous and lies underneath compact bone.
What are Oestoblasts; identity and function
Bone forming cells. Lay down more collagen, starting the mineralisation process
What are Oestocytes; identity and function
Mature bone cells derived from oestoblasts trapped in the ECM. Maintain bone tissue, have gap junctions.
Name the 4 cell types in bones
osteogenic cells, osteoblasts, oestocytes, oestoclasts
What are Oesteogenic cells; identity and function
Mesenchymal stem cells that develop, start to lay down collagen, become trapped and become oestoblasts
What are Osteoclasts; identity and function
Large multinucleated monocytes that break bones to access stored minerals.
Fluid connective tissue (liquid)
Blood
Blood consists of
blood plasma (a liquid ECM) and formed elements= cells (red cells, white cells and platelets)
The protein fibres of ECM are secreted by
CT cells in the ECM
What dictates the qualities of the connective tissue
The structure of the ECM
Proteoglycans look like a
brush (core protein = handle, GAGS = bristles)
Hyaluronic Acid is a viscous slippery substance that
- binds cells together,
- lubricates joints and
- maintains the shape of the eyeball
Chondroitin Sulphate:
support and provide the adhesive features of cartilage, bone, skin, blood vessels.
Keratan Sulphate found in
bone, cartilage, cornea of the eye
Dermatan Sulphate found in
tendons, blood vessels,
heart valves
Abnormal Periorbital ECM and thyroid disease caused by
the deposition of GAGs and the influx of water increasing orbital contents
3 different types of tissue fibres in the ECM
Collagen, reticular and elastic
Collagen fibres are common in bones, cartilage, tendon and ligaments. Feature:
very strong but flexible to resist pulling forces
Reticular fibres form networks in vessels and through adipose, smooth muscle and nerve fibres
Thinner and branching, they form part of the basement membrane providing strength and support
Elastic fibres are a thin fibrous network found in the skin, blood vessels and lung and consist of
protein elastin surrounded by glycoprotein fibrillin to give strength and stability; can stretch 150%
Fixed phagocytes include
dust cells (lungs), Kupffer cells (liver) langerhans cells (skin)
Connective tissue can either be
Embryonic or Mature
Mesenchyme CT: what category is it, what is its structure, function and location
Embryonic CT: structure is mesenchymal cells in a semi-fluid GS containing reticular fibres. Function is form all other connective tissues. Found under skin and along developing bones of embryo
Mucous CT :what category is it, what is its structure, function and location
Embryonic CT: structure is widely scattered fibroblasts embedded in jelly like GS containg collagen fibres.
Function is to support, it is found in the umbilical cord of the foetus.
Reticular CT;what category is it, what is its structure, function and location
It is loose CT. Structure is fine interlacing network of reticular fibres and reticular cells.
Function/location is to form the stroma (supporting network) of organs, binds smooth muscle tissue cells, filters and removes worn out blood cells in spleen and microbes in lymph nodes. Also in reticular lamina of BM.
Dense irregular CT: what is its structure, function and location (looks like fatty meat).
Structure: irregularly arranged collagen fibres with a few fibroblasts.
Func; provides tensile (pulling strength) in different directions. Occurs in sheets encapsulating organs, and it is the tissue beneath skin around muscles.
Elastic CT: what category is it, what is its structure, function and location
(unstained tissue is yellow)
structure is elastic fibres with fibroblasts.
Allows stretching of the organs but strong enough to recoil back to shape. Found in many respiratory tissues and arteries.
Fibrocartilage: what is its structure, function and location
chondrocytes among clearly visible thick bundles of collagen fibres within the ECM. No perichondrium. Supports and joins structures together. Found at the pubic symphysis, intervertebral discs.
What are the structural features consistent with all cartilage : supply, fibres and GS, cells,
It doesn’t have a nerve or blood supply.
It has a dense network of collagen and elastic fibres firmly embedded in chondroitin sulphate component of GS. Mature cartilage cells called chondrocytes occur in spaces in the ECM called lacunae.
What is the perichondrium
Thin layer of dense irregular CT that surrounds the surface of cartilage and supplies new cartilage cells
Elastic cartilage: what is its structure, function and location ( indigo eyes on stalks)
chondrocytes in threadlike network of elastic fibres. perichondrium present. Provides strength and elasticity. Found in epiglottis, ear and auditory tubes.
Spongey bone : structure function
Structure: Lacks osteons has columns of bone called trabeculae. Func: stores triglycerides (YM) and produces blood cells. (RM)
What is the basic unit of Compact bone and what are the four parts of this basic unit
Basic unit= osteon
Osteons are made of Lamellae, Lacunae, Canaliculi and Central Haversian canal.
What are Lamellae
concentric rings of ECM storing mineral salts (CaP + CaOH= hydroxyapatite and collagen) that give hardness
What are Lacunae
small spaces between lamellae that contain mature bone cells (psteocytes)
What are Canaliculi
minute canals (containing ECM and osteocytic processes) that radiate from lacunae and provide route for O2, nutrients and waste
What is the Central Haversian canal
Centre bit that contains blood vessels and nerves.
What do Basophils do
release substances like histamine that intensify the inflammatory reaction
What do Eosinophils do
fight parasitic worms
