Histology: Connective Tissue Flashcards
What is the function of connective tissue? (11)
- Found throughout the body
- Provides elasticity, structure, protection & transport
- Support and connect different tissue types
- organs, blood vessels, links epithelial tissues to underlying tissue types
- Support softer organs of the body
- Connect parts of the body
- Store fat
- Produce blood cells
- Transport gasses, nutrients and waste products
- Protect (including immune defense)
- Contain cells embedded in nonliving extracellular matrix
What is the structure of the matrix?
Web of fibres embedded in a liquid (jelly-like or solid foundation) Fibroblasts present – secrete fibre
proteins and create fibres—> give tissue structure and mechanical properties: Dense thick Collagen, Thin Reticular Fibres, Elastin stretchy and playable.
What is the ground substance?
Liquid, intermediary substance where dissolved particles(electrolytes ) float in
Macrophages – engulf foreign particles and cell debris (phagocytosis).
Two main types with subtypes with characteristics varying greatly
❑ Connective tissue proper: (2)
- Loose connective
* Dense/ dense fibrous
Two main types with subtypes with characteristics varying greatly
❑ Specialised (4)
- Adipose
- Cartilage
- Bone
- Blood
What are collagen fibres? (2)
- Collagen fibres are the strongest and most abundant of all the connective tissue fibres.
- Collagen fibres are fibrous proteins and are secreted into the extracellular space and they provide high tensile strength to the matrix.
What are the elastic fibres?
Elastic fibres are long, thin fibres that form a branching network in the extracellular matrix. They help the connective tissue to stretch and recoil.
What are reticular fibres?
Reticular fibres are short, fine collagenous fibres that can branch extensively to form a delicate network
What is loose connective tissue? (3)
- Most abundant
- Amorphous matrix
- Has fibroblasts, macrophages, mast cells (secrete histamines and heparin and are involved in allergic response)
What is the function of the loose connective tissue? (3)
- Binds epithelia to underlying tissues
- Holds organs in place
- Loose weave of fibres (all three types)
Different cells of loose ct- function (3)
- fibroblasts
- mast cells
- macrophages
What are fibroblasts?
Can migrate toward wounded tissue, and produce fibers (secretes collagen & elastin proteins; requires vitamin C), to effectively seal off the injured area.
What are mast cells?
Secrete histamine & heparin; are involved in the allergic response.
What are macrophages?
Engulf bacteria or other foreign particles.
What is fibrous connective tissue?
-short bands / bundles of dense collagenous fibres
What are the types of fibrous connective tissue? (2)
- ligaments (connect bones at joints)
* tendons (attach muscles to bones)
Specialised matrix for particular functions 4 types:
1) Cartilage -rubbery matrix
2) Bone - solid matrix
3) Adipose - hardly any matrix
4) Blood-fluid matrix
Matrix =
collagen (area around cells)
What are the features of the matrix?
- Firm, strong and flexible
Chondroitin sulfate: (2)
- Rubbery
- Living chondrocytes in lacunae
What are lacunae? (2)
- Lacunae: Nests for chondrocytes
- Secrete collagen and chondroitin sulphate
Where is the collage in the matrix found?
-Location: between bones, discs that act as cushions between vertebrae, larynx, trachea
What are the chondrocytes?
- Chondrocytes - Cells
- Nutrients exchanged through diffusion
What are the functions of cartilage? (4)
- Maintains shape
- Resists compression
- Cushions and reduces friction
- Flexible shock absorber
Transitional tissue from which bone develops….
maintains the shape of certain body parts (nose, ears), cushions vertebrae (vertebral disks), lines joint cavities
Does cartilage lack bloody supply?
• Lacks lymphatic or blood supply and the movement of waste and nutrition is chiefly
via diffusion to and from adjacent tissues.
What are the lacunae arranged in?
The lacunae are arranged in nests.
What is hyaline cartilage?
Hyaline cartilage is white and semi-transparent and helps in providing protection and cushioning. It does not contain any blood vessels. Ossifies to the bone in the foetus.
How do chondrocytes acquire nutrition?
Chondrocytes acquire their nutrition through the diffusion of tissue fluids from blood vessels through the solid matrix.
What is the function of hyaline cartilage?
Provides stiff but somewhat flexible support; reduces friction between bony surfaces.
What is the function of elastic cartilage?
Provides support, but tolerates distortion without damage and returns to its original shape.
What is the function of fibrous cartilage?
Resists compression; prevents bone-to-bone contact; limits relative movement
What is bone?
Bone is a mineralised connective tissue
• Stronger than cartilage but not as flexible
Endochondral ossification:
Forms within and replaces cartilage
What are osteoblasts? (2)
- (bone-forming cells) deposit matrix of collagen.
* Calcium, magnesium, and phosphate ions combine into a hard mineral within the matrix
What are the functions of bone? (3)
- protection
- support for muscle attachment & movement
- forms the skeleton
What is adipose tissue? (2)
- Few fibres, no ground substance
* Adipocytes contain fat deposits
What is the location of adipose tissue? (2)
- under skin
2. surrounding organs
What are the functions of adipose tissue? (4)
- insulation
- energy storage
- cushioning
- Fat cells; functions in insulation, protection, and energy storage
What is adipose tissue described as?
Adipose tissue is described as loose connective tissue because of the matrix and way cells are arranged but it is considered and classified under one of the 4 specialised connective tissue types
What are adipocytes?
- Adipocytes (adipose tissue cells) are filled with lipid (fat) droplets surrounded by a thin layer of
cytoplasm.
The different cells (varying in shape and function) of the loose connective tissue contain _____ _____.
cytoplasmic matrix
What is the function of loose/Areolar connective tissue?
- Loose/Areolar connective tissue holds the organs in place and also attaches epithelial to underlying
tissues.
What are the components of the fluid matrix (liquid extracellular matrix)? (5)
plasma water salts dissolved proteins Blood cells:
What do erythrocytes do?
Transport of oxygen and carbon dioxide
What do leukocytes do? (2)
- Fighting diseases
- Preventing infection and getting rid of foreign matter
Platelets (__________ = fragments) —-> Blood clotting
thrombocytes
True or False,
Blood in vertebrates is connective tissue.
True, blood in vertebrates is a connective tissue consisting of several kinds of cells suspended in a liquid matrix called plasma.
• The cellular elements occupy about ___% of the volume of blood
45%
• The plasmatic elements occupy about __% of the volume of blood
55%
What does plasma contain?
Plasma contains inorganic salts as dissolved ions, sometimes called electrolytes
What is do plasma proteins? (5)
- influence blood pH
- help maintain osmotic balance
- lipid transport
- immunity
- blood clotting
• Particular plasma proteins function in ____ transport, ______ , and ____ clotting.
lipid
immunity
blood
Cellular elements
• Suspended in blood plasma: (3)
- Red blood cells (erythrocytes) transport O2
- White blood cells (leukocytes) function in defence
- Platelets - cells that are involved in clotting
What do erythrocytes contain?
- Contain haemoglobin (the iron-containing protein that transports oxygen)
How does oxygen diffuse into the lung?
-Oxygen from the lungs diffuses into erythrocytes and 4 molecules of oxygen bond with each haemoglobin molecule and oxygen is then released into tissue cells
What is the function of erythrocytes?
- Specialized cells that circulate through the body and deliver oxygen to tissues.
How does the shape of erythrocytes help it achieve its function? (4)
- Small and biconcave (thinnest in the centre) and do not contain mitochondria or a nucleus when mature.
- These characteristics allow red blood cells to effectively perform their task of oxygen transport.
- Small size and biconcave shape increase the surface area-to-volume ratio, improving gas exchange, while the lack of a nucleus makes additional space for haemoglobin, a key protein used in oxygen transport.
- Lack of mitochondria keeps red blood cells from using any of the oxygen they’re carrying, maximizing
the amount delivered to tissues of the body.
What is sickle cell disease? (4)
- In sickle cell disease, a single gene mutation alters the shape of haemoglobin and they lock together into rigid rows causing deformation of red blood call shape
- These sickle-shaped red blood cells are harder and stickier and no longer flows smoothly through the blood vessels
- These cells can often pile up & block a vessel completely
- This keeps oxygen from reaching the places need be causing a variety of complications
Small changes at the cellular level can cause a _____ of complex differences and issues.
cascade
What does sickle cell affect?
- Sickle cell affects the red blood cells; haemoglobin floats freely & independently in the biconcave disc shape —> ordinary red blood cells
- This keeps oxygen from reaching the places need be causing a variety of
complications: (5)
> pain in organs that are starved of oxygen (blood vessel position determines the position of the pain in
the organ/tissue)
blockage in spleen—> weakened immune system
blockage in the lungs—>fever & difficulty breathing
blockage near eyes—>vision problems & retina, detachment
blockage in the brain—>stroke
Do sickle blood cells live for?
- Sickle blood cells also do not live for long—> patients will live with a constantly depleted red blood cell concentration—> sickle cell anaemia
True or false
Sickle cells were originally the result of a favourable evolutionary event
True,
—> Sickle cells would not allow for malaria to be spread as the sickle cells would not allow incubation & spread —> Malaria Resistance
- Unfortunately inheriting the sickle cell gene from both parents created an environment for sickle cell anaemia—> the adverse effect over time
