Connective tissue

Question 1

connective tissue structure

Answer 1

CT = ECM + Cells
ECM = Protein fibres + Ground Substance

Question 2

Protein fibres: collagen

Answer 2

Thick
Very strong but flexible to resist pulling forces
Bundle arrangement adds great tensile strength to tissue
Chemically consists of collagen (protein)
Common in connective tissues e.g. bone, cartilage, tendons (bone to muscle) and ligaments (bone to bone)

Question 3

Protein fibres: Reticular

Answer 3

Consists of collagen arranged in find bundles with coating of glycoprotein
Made by fibroblasts
Provides strength and support
Forms part of basement membrane
Thinner, branching and spreads through tissue
Support walls of blood vessels
Form a network around cells in some tissues e.g. adipose tissue, nerve fibres, smooth muscle tissues

Question 4

Protein fibres: Elastic

Answer 4

Thinner than collagen fibres, therefore more flexible
Joins together to form fibrous network within connective tissue
Consists of elastin (protein) surrounded by glycoprotein
Fibrillin adds strength & stability
Can be stretched 150% without breaking
Found in skin, blood vessels and lungs

Question 5

Cells: fibroblasts

Answer 5

Widely distributed in connective tissues
Migratory
Large, flat cells
Secrete fibres and ground substance

Question 6

Cells: Adipocytes (fat cells)

Answer 6

Under skin & around organs
Stores fat (triglycerides)

Question 7

Cells: Macrophages (histiocytes)

Answer 7

Type of white blood cell
Phagocytic cells. Protects body by ingesting pathogens, bacteria, dead/dying cells
Irregular shape with short branching projections
Fixed form: Dust cells in lungs. Kupffer cells in the liver. Langerhans cells in skin.
Wandering form: Sites of infection/inflammation/injury

Question 8

Cells: Plasma cells

Answer 8

Developed from B-lympocyte
Produces antibodies
Common in gut, lungs, salivary glands, lymph nodes, spleen, red bone marrow
Important part of immune response

Question 9

Cells: Mast cells

Answer 9

Produces histamine which dilates vessels (inflammatory response)
Located alongside blood vessels
Can bind to, ingest and kill bacteria

Question 10

Cells: Leukocytes

Answer 10

White blood cells
Migrate from blood into CT
Neutrophils gather at site of infection
Eosinophils migrate to site of parasitic invasions and allergy responses

Question 11

Ground substance

Answer 11

Material between cells and fibres
Can be: 
Fluid
Semifluid
Gelatinous
Calcified

Contains:
Water
Hyaluronic acid
Chondroitin sulfate
Dermatan sulfate
Keratan sulfate

Question 12

Embryonic CT

Answer 12

Mesenchyme

Mucous

Question 13

Mature CT: Proper: Loose: Areolar

Answer 13

Most common CT
Many cells & fewer fibres
Widely distributed
Strength, elasticity and support

Question 14

Mature CT: Proper: Loose: Adipose

Answer 14

Many cells & fewer fibres
Adipocytes dominant (lymphocytes & fat cells)
Central triglyceride droplet
Found with areolar CT including fibroblasts
Insulation, energy source, temperature control
White adipose: energy storage
Brown adipose: heat production

Question 15

Mature CT: Proper: Loose: Reticular

Answer 15

Fine interlacing network of reticular fibres and reticular cells
Forms stroma of liver, spleen, lymph nodes, red bone marrow, reticular lamina of BM, around blood vessels and muscles.
Binds smooth muscle tissue cells
Filters and removes: worn out blood cells in spleen & microbes in lymph nodes.

Question 16

Mature CT: Proper: Dense: Elastic

Answer 16

Predominantly elastic fibres with fibroblasts between them
Unstained tissue is yellowish
Located in lung tissue, walls of elastic arteries, trachea, bronchial tubes, true vocal cords, suspending ligaments of penis, some ligaments between vertebrae.
Allows stretching of various organs
Strong
Can recoil back to original shape after stretch
Elasticity in lung tissue for breathing, in arteries for heart beat and maintaining blood flow

Question 17

Mature CT: Proper: Dense: irregular

Answer 17

Collagen fibres irregularly arranged with a few fibroblasts
Fasciae (sheet of CT) beneath skin, around muscles and other organs
Reticular regions of dermis
Fibrous pericardium of heart
Periosteum of bone
Perichondrium of cartilage
Joint capsules
Membrane capsules in kidneys, liver, tests, lymph nodes, heart valves
Provides tensile strength in many directions

Question 18

Mature CT: Proper: Dense:

Answer 18

Tendons
Ligaments
Aponeurosis
Shiny white ECM
Mainly collagen fibres regularly arranged in bundles with fibroblasts in rows
Provides strong attachment between structures
Withstands tension along axis of fibres

Question 19

Supporting CT : Cartilage: Hyaline

Answer 19

Dense network of collagen and elastic fibres
Abundant
Flexibility and movement
Blueish white, shiny
Anterior ends of ribs, ends of long bones
Respiratory cartilage: nose, trachea, bronchi, nasal septum

Question 20

Supporting CT : Cartilage: Elastic

Answer 20

Chondrocytes in threadlike network of elastic fibres within ECM - with perichondrium
Provide strength and elasticity
Lip on top of larynx, part of external ear, auditory tubes.

Question 21

Supporting CT : Cartilage: Fibrous

Answer 21

Chondrocytes among clearly visible thick bundles of collagen fibres
With ECM- lacks perichondrium
Support and join structures together (strongest cartilage)
Pubic symphysis, intervertebral discs, menisci of knee, portions of tendons that insert into cartilage

Question 22

Compact Bone

Answer 22

Outer layer of bone
Forms shaft of long bones
Made of many osteons (haversian systems)
Contains lamellae, lacunae, osteocytes, canaliculi and central canals
Osteocytes
 mature bone cells derived from osteoblasts trapped within ECM. 
Maintain bone tissue
Involved in exchange of nutrients
Have gap junctions