Chapter 4: Tissue Level of Organization Part 2 Flashcards
Connective Tissues
This material is located between widely spaced cells, and consists of protein fibres and ground substance.
Extracellular Matrix
Functions of connective tissues
bings together, supports, strengthens other body tissues, protects and insulates internal organs, compartmentalizes structures, major transport system within the body (blood), most stored energy reserves is here and the main source of immune response
Fibroblasts to fibrocytes
Loose and dense connective tissue cells
Chondroblasts and chondrocytes
Cartilidge cells
Osteoblasts and osteocytes
Bone cells
What cells retain the capacity for cell division and secrete the extracellular matrix of the connective tissue?
Blast cells
In some tissues when a blast cell (immature cell), produces extracellular matric and then differentiate into a mature cell it is then called?
A -cyte cell
eg fibrocyte, osteocyte, chondrocyte
Matured cells (-cytes) have reduced capacity for what?
What are they mostly involved in?
Reduced capacity for:
Cell division and extracellular matrix formation
Mostly:
Monitor and maintain extracellular matrix
Cells of connective tissues:
Fibroblasts
Macrophages
Plasma Cells
Mast Cells
Adipocytes
Leukocytes
Fibroblasts
large, flat cells with branching processes
Present in all general connective tissue and most numberous
Macrophages
Phagocytes produced from monocytes
Fixed Macrophages - reside in a particular tissue
Wandering Macrophages - ability to move throughout and gather at sites of inflammation or infection
Plasma cells (plasmocytes)
found in many places in the body
Mostly reside in connective tissue, especially in the gastrointestinal and respiratory tracts
Secrete immunoglobin and antibodies
Mast cells
Mastocytes
Involed in the inflammatory repsonse and can also bind to, ingest and kill bacteria
Adipocytes
Fat cells; cells cells that store triglycerides
Leukocytes
White blood cells
Not usually significant number in connective tissue but enter connective tissue from blood stream when needed
What are the two main components of connective tissue extracellular matrix?
- the ground substance
- the fibres
Describe ground substance
- may be fluid, semifluid, gelatinous or calcified
- supports cells, binds them together, stores water and provides a medium for exchange of substances between the blood and cells
- Influences how tissues develop, migrate, proliferate and change shape and in metabolic functions
- contains water and large organic molecules, many complex combinations of polysaccharides and proteins
Hyaluronic acid
binds cells, lubricates joints and helps maintain the shape of eyeballs
What cells produce hyaluronidase and what does it do?
white blood cells, sperm cells, and some bacteria
breaks down hyaluronic acid and therefore causes ground substance to become more liquid, allowing easier passage into the connective tissue
ADhesion proteins
link components of ground substance to one another and teh surfaces of cells
Fibronectin
The main adhesion protein of the connective tissues
Links collagen fibres and ground substance together; links cells to ground substance
Three types of fibres in extracellular matric
- Collagen fibres
- Elastic FIbres
- Reticular Fibres
These fibres are very strong and resist pulling or stretching but are not stiff.
Made of collagen protein which is the most abundant protein in the body (25%)
Found in most connective tissues - especially found in bone, cartilage, tendones and ligaments
Collegan Fibres
These fibres are smaller than collagen fibres
They branch and join together to form a fibrous network
COnsists of molexules of the protein elastin, surrounded by a glycoprotein called fibrillin (adds strength and stability)
Can be stretched up to 150% their relaxed length
Can return to original shape after being strches (elasticity)
Found in skin, blood vessel walls and lung tissue
Elastic FIbres
These fibres consist of collagen molecules arranged in bundles with a coating of glycoprotein
They provide support in the walls of blood vessels and form a network around cells in some tissues (eg areolar, adipose tissues, nerve fibres)
Produced by fibroblasts and are much thinner than collagen fibres
Form branching networks
Provide support and strength
Plentiful in reticular connective tissue which forms the stroma of many soft organs and also help form basement membrane
Reticular Fibres
What is stroma?
Supporting framework
Connective TIssues Classification Chart
I. Embryonic connective tissue
A. Mesenchyme
B. Mucous (mucoid) connective tissue
II. Mature connective tissue
A. Connective tissue proper
1. Loose connective tissue
a. Areolar connective tissue
b. Adipose tissue
c. Reticular connective tissue
2. Dense connective tissue
a. Dense regular connective tissue
b. Dense irregular connective tissue
c. Elastic connective tissue
B. Supporting connective tissue
1. Cartilage
a. Hyaline cartilage
b. Fibrocartilage
c. Elastic cartilage
2. Bone tissue
a. Compact bone
b. Spongy bone
C. Liquid connective tissue
1. Blood
2. Lymph
Embryonic Connective Tissue
- connective tissue present in the embryo or a fetus
- composed of mesenchyme and mucoid connective tissue
Mature Connective Tissue
- connective tissue that is present at birth and persists throughout life
Comprised of:
A. Connective TIssue Proper
B. Supporting connective tissue
C. Liquid COnnective Tissue
Embryonic Connective Tissue
A. Mesenchyme Connective Tissue
B. Mucoid Connective Tissue
Primarily in the embryo (conception to 2months of pregnancy) and the fetus (3 montsh pregnancy to delivery)
Mature Connective Tissue
A. Connective Tissue Proper
Flexible and has a viscous ground substance with abundant fibres
Connective Tissue Proper
1. Loose connective tissue proper
Fibres are loosely arranged between cells
a. Areolar connective tissues
b. adipose tissue
c. reticular connective tissue
- Loose Connective Tissue Proper
a. Areolar connective tissues
- most widely distributed
- fibres, cells embedded in semifluid ground substance
- paccking material around nearly every body structure
- gives strength, elasticity and support
Loose connective tissue proper
b. Adipose tissue
- adipocytes that store triglycerides as a large, central droplet
- located everywhere areolar tissue is located
- reduces heat loss, is an energy reserve, supports and protects organs
Brown Adipose tissue in newborns generates heat
- source of stem cells
Loose Connective Tissue Proper
C. Reticular Connective Tissue
- fine interlacing network of reticular fibres (thirn collagen fibre) and reticular cells
- located in stroma of liver, spleen and lymph nodes, red bone marrow, reticular lamina, around blood vessels and muscles
- Forms stroma, bings smooth muscle tissue to cells, filters and removes worn out blood cells in spleen and microbes in lymph nodes
Connective Tissue Proper
2. Dense Connective Tissue
- Contains more fibres that are thicker and more densely packed and have fewer cells than loose connective tissue
- dense regular connective tissue
- dense irregular connective tissue
- elastic connective tissue
Mature Connecting Tissue
1. Connecting Tissue Proper
a. loose connective tissue
b. Dense connective tissue
i. dense regular connective tissue
shiny white extracellular matrix, mainly collegan arranged regularly in bundles with fibroblasts between them in rows
collagen fibres are non living, slow to heal
forms tendons, most ligaments, and aponeuroses (muscle to muscle or bone to bone) sheet like tendones
strong attachement between various structures, withstands tesion on long axis of fibres
Dense Connective Tissue Proper
ii. dense irregular connective tissue
made up of collagen fibres but irregularly arranged with a few fibroblasts
- usually occurs in sheets 9 fasciae, reticular region of dermis, joint capsuble, membrane capsules
- tensile strength in many directions
Dense Connective Tissue Proper
ii. Elastic Connective Tissue
mostly elastic fibres with fibroblasts between them; unstained tissue is yellowish
- located in lungs, walls of elastic arteries, trachea, bronchiol tubes, true vocal cords, suspensory ligaments of penis, some ligaments between vertebrae
- allows stretching of various organs; strong and recoils
II. Mature Connective Tissue
A. Connective Tissue Proper
i. Loose - areolar, adipose, and reticular
ii. Dense - dense regular, dense irregular, elastic
B. Supporting Connective Tissue
Supporting connective tissue
1. Cartilage
2. Bone Tissue
Mature Connective Tissue
B. Supporting Connective Tissue
i. Cartilage
Consists of a dense network of collagen fibres and elastic fibres firly embedded in chondroitin sulfate (gel like component of ground substance)
can endure more stress than loose or dense connective tissue
Resilience is due to chondroitin sulfate
Few cells, large extracellular matrix
No nerves or blood supply
Lucanae
chondrocytes occur singly or in groups within spaces called lucanae
Perichondrium
dense irregular connective tissu that surrounds the surface of most cartilage and contains blood and nerves and is source of new cartilage cells
Cartilage is a precursor to:
Bone
Where is cartilage found after birth in the body
growth plates
joints
Three types of cartilage
a. hyaline
b. fibrocartilage
c. elastic
Two basic patterns of cartilage growth:
- Interstitial growth
- Appositional growth
Interstitial growth of cartilage
growth from with in the tissue
existing chondrocytes divide and also deposit increasing amount of extracellular matrix, which pushes the cells away from each other, causing tissue to grow rapidly
growth pattern when young and pliable
Appositional growth of cartilage
when cells in the inner layer of the perichondrium differentiate into chondroblasts. The chondroblasts surround themselves with extracellular matrix and become chondrocytes
continues into adolescence
II. Mature CT
A. CT Proper
i. Loose
II. dense
B. Supporting CT
i. Cartilage
Hyaline -
Fibrocartilage -
Elastice Cartilage -
Hyaline Cartilage
- resilient gel ground substance
- appears bluish white in body
- chondrocytes in lucanae surrounded by perichondrium
- most abundant - ends of long bones, anterior ends of ribs, nose, parts of larynx, trachea, bronchi, brochial tubes, embryonic and fetal skeleton
- provides smooth surface for movement at joints, flexibility, and support
- the weakest type
can be fractured
Fibrocartilage
choncdrocytes amoung clearly visible thick bundles of collagen fibres within extracellular matrix
- no perichondrium
- located in pubis symphysis, intervertebral discs, menisci of knee, portions of tendons that insert into cartilage
- support and join structures together
- stength and rigidity make it strongest type of cartilage
Elastic Cartilage
Chondrocytes in a thread like network of elastic fibres within extracellular matrix
has perichondrium
- epiglottis, auricle, eustachian tubes
- strength and elasticity; maintains shape of certain structures
Supporting CT
i. Cartilage
a. Hyaline
b. Fibrocartilage
c. Elastic cartilage
ii. Bone Tissue
Bone (osseous tissue)
- compact
- spongy
-stores phosphorous and calcium
-houses red bone marrow
-contains yellow bone marrow (triglyceride storage)
Bone Tissue
i. Compact Bone
Osteon or haversion system is the basic unit of compact bone
Osteon (Haversion System) contains 4 parts
- Lamellae
- Lucanae
- Canaliculi
- Central Canal
Haversion System (Osteon)
1. Lamellae
“little plates”
concentric rings of extracellular matrix that consist of mineral salts (compressive strength) and collagen fibres (tensile strength)
- these are the cause of the nature of compact bones
Lacunae
Spaces between lamellae that contain osteocytes
Canalculi
Project from lacunae, minute canal networks that contain the processes of osteocytes for nutritents and wastes to be transfered
Central Canal of haversion system (aka haversion canal)
contains the blood vessels and nerves
Bones
i. Compact
ii. Spongy
Trabeculae are basic units of spongy bone
Consist of:
- lamellae
- lacunae
- Osteocytes
- canaliculi
No central canal. Red bone marrow between trabeculae
Supportive CT
A. Cartilage
B. Bones
C. Liquid CT
Blood tissue
Lymph
Extracellular matrix is a liquid
Blood Tissue
Extracellular matrix is plasma - yellow mostly water fluid with disolved substances
Formed elements (red blood cells, white blood cells, platelets)
Lymph
Extrecellular fluid that flows in lymphatic vessels
consists of several types of cells in a clear liquid similar to blood plasma but with less protein
composition varies from one part of body to another
