Introduction to Body Tissues, Organs + Organ Systems Flashcards
What is the definition of a tissue?
a collection of cells and their products in which one cell predominates
What is the definition of an organ?
A distinct collection of tissues forming a structure within an animal which is adapted to perform a specific purpose
What is the definition of a system?
A collection of organs and tissues which are related by function
What are the 3 basic components of tissues?
Cells
Intercellular substances
Body fluids
What is a feature of the cells of a tissue?
One type of cell forms the majority, and gives the tissue type its name.
e.g. muscle tissue consists mostly of muscle
cells
Where is the intercellular substances making up a tissue produced?
Produced by the cells and lie in the space between them
What is the body fluid making up a tissue?
Interstitial fluid flows through specialised channels running through the tissue
What are the 3 layers in the embryo that all adult tissues develop from?
- Ectoderm
- Endoderm
- Mesoderm
What is derived from the ectoderm?
Outer surface, Central nervous system, Neural crest
e.g. Epidermis, CNS, PNS, Melanocytes
What is derived from the endoderm?
Digestive tube, Pharynx, Respiratory tube
e.g. Gut, Lungs, Liver, Pancreas, Gall bladder,
Thymus, Thyroid
What is the derived from the mesoderm?
Dorsal, Paraxial, Intermediate, Lateral, Head
e.g. Notocord, Muscle, Bone, Dermis, Heart,
Kidney, Somatic Gonad, Vasculature, Blood
What are the 4 primary types of tissues that make up the entire body?
- Epithelial tissue
- Connective tissue (support)
- Muscle tissue
- Nervous tissue
What is the structure and an example of epithelial tissue?
Cells adjacent with little matrix
e.g. skin (epidermis), lining of hollow organs +
tubes, glandular epithelium
Where is Hyaline cartilage found?
Found in growing long bones, trachea, bronchi, articulating surfaces of bone in synovial joints, cartilage of nose and in larynx.
What is hyaline cartilage made up of?
Consists of a sparse number of chondrocytes within a matrix if proteoglycans and collagen fibres.
Where is fibrocartilage found?
Found in intervertebral disks and in the pubic symphysis
Collagen fibres are arranged in thick bundles able to withstand large pressure
What is the structure and an example of connective tissue?
Abundant extracellular matrix, strong - for support
e.g. bone, cartilage, tendon, loose connective tissue
What is the structure and an example of muscle tissue?
Highly contractile cells create movement
e.g. striated, cardiac, smooth
What is the structure and an example of muscle tissue?
Conduct electrical signals (action potentials) along cell membranes
e.g. brain & spinal cord, cranial nerves,
peripheral nerves, ganglia
What type of tissue is bone?
Bone is a connective tissue
What cells is bone mostly made up of?
Contains various cell types but osteocytes / osteoblasts / osteoclasts predominate
What do fibroblasts do?
Secrete extracellular matrix proteins
What do adipocytes do?
Store fat
What do smooth muscle cells do?
Surround blood vessels to give vascular tone
What do osteoblasts do?
Make and remove bone
Secrete type 1 collagen
Add calcium and phosphate to mineralise the bone
What do osteoclasts do?
Make and remove bone
Secrete proteases and acid to break down bone
Seal themselves to bone surface forming a digestive zone
Required for bone remodelling - constant process
What are osteocytes and what do they do?
Mature cells lying within the bone itself ‘entrapped’ by osteoblasts, sense stress
What do chondroblasts / chondrocytes do?
Make cartilage
How do chondroblasts / chondrocytes make cartilage?
Secrete a mixture of type 2 collagen and proteoglycans, forming a cartilage template in the shape of the final bone.
Cartilage remains as smooth surface of articulated joints
Chondroblasts eventually become surrounded by ECM and differentiate into chondrocytes.
What is required for bone formation?
= a community of cells
=> Chondroblasts/chondrocytes, Osteoblasts,
Osteoclasts, Osteocytes
What do osteoblasts do?
Secrete type 1 collagen
Add calcium and phosphate to mineralise the bone
What is dense connective tissue made up of?
Densely packed collagen bundles with few fibroblasts and other cells in between
How are the fibres in dense connective tissue arranged?
In two formations
1. Regular formation
2. Irregular formation
What are ligaments made up of?
Composed of dense regular collagenous connective tissue.
- Run in same direction giving high tensile
strength.
What is dense regular formation of connective tissue?
Fibres are in 1 main direction
Fibrous connective tissue e.g. tendons
(strong bands of fibrous tissue linking muscle to bone, and ligaments, linking bone to bone)
What is dense irregular formation of connective tissue?
Fibres in random mesh.
Seen in the dermis of the skin and capsules of joints as well as organs capsules like testis and lymph nodes.
Layers of moist fascia’s, serous membranes and aponeuroses (a white fibrous tissue)
What are tendons made from?
Composed of dense regular collagenous connective tissue.
Collagen fibres tend to run in the same direction and can withstand forces running in the same direction of fibres, giving them high tensile strength and ability to resist stretching forces.
What is the function of tendons?
- Connect muscle to bone
- Optimise muscle position and length
What is the structure + function of aponeurosis?
- Wide flat sheet rather than round tendon
- Attaches muscle to bone or other muscle
What is the structure of the epithelium?
Lining sheets of cells with little matrix. Basal surface anchored.
What is the function of the epithelium?
- Separates organs and protects the body.
- Covers the body surface and organs, cavities
and tubes within it.
-Forms the lining of most organs, may be
secretory (e.g. sweat, saliva, mucus etc) or
absorbent (water, metabolites, waste)
e.g. Skin (superficial layer = epidermis) - lining
of gastrointestinal tract, respiratory tract
and glands
Is the skin an example of a tissue, organ or organ system?
Skin (integument) = an organ - continuous covering of entire body
What three tissue layers is the skin comprised of?
- Epidermis
- Dermis
- Hypodermis
What is the different levels that make up the body (from smallest to biggest) ?
Cell –> Tissue –> Organ –> Organ system –> Organism
What are the separate areas called that the body can be divided into?
= Body cavities
What are the 8 different body cavities?
- Cranial cavity
- Dorsal cavity
- Thoracic cavity
- Spinal cavity
- Ventral cavity
- Abdominal cavity
- Pelvic cavity
- Abdominopelvic cavity
What makes up the thoracic cavity?
Heart, lungs + associated structures within the bony thoracic cage (ribs, thoracic spine & sternum)
What makes up the abdominal cavity?
Abdominal viscera - GI tract, glands + urogenital system, associated nerves and vessels.
What makes up the pelvic cavity?
Urinary bladder, rectum and reproductive organs
What is areolar tissue?
A loose connective tissue that holds organs in place and attaches epithelial tissue to other underlying tissues.
Also is a reservoir of water and salts for surrounding tissues.
What is bone marrow?
Soft spongy tissue with many blood vessels, found in the centre of most bones.
Contains blood stem cells that can become red blood cells, white blood cells or platelets.
What is reticular tissue?
A loose connective tissue - reticular fibres are most predominant fibres.
Found around the kidney, liver, spleen and lymph nodes.
What does the Latin root ‘blast’ mean?
bud or shoot
or having the same parents
What does the Latin root ‘clast’ mean?
= to break down, to destroy
