Tissues Flashcards
Define tissue
Groups of cells with similar structures that act together to perform a specific function
What are the four types of tissue?
- Epithelial tissue
- Nervous tissue
- Muscle tissue
- Connective tissue
Where is epithelial tissue found?
- Skin
- Membranes that line body cavities and tracts
What is the function of epithelial tissue?
- Dense cellular sheet for covering/protecting/lining cavities and tracts
- Forms skin
What are the features of epithelial tissue?
- Strong connections between cells
- No blood supply (rely on extracellular tissue fluid)
- Supported by basal lamina complex
- Can form glands to secrete various substances
What are the six different types of epithelial tissue?
- Simple squamous epithelium (thin delicate sheet lining alveoli of lungs with no barrier to gaseous diffusion)
- Stratified squamous epithelium - can withstand abrasion and forces (e.g. vocal cords, oral cavity, skin)
- Simple columnar epithelium (small bronchioles)
- Psuedostratified columnar epithelium - single layer appearing to be multiple layers because the nuclei are at different levels (e.g. respiratory tract, middle ear)
- SImple/stratified cuboidal (kidney nephrons)
- Glands - single epithelial cells (goblet) or groups forming a duct or gland
Where is nervous tissue found?
CNS and PNS
What is the function of nervous tissue?
Transmit information
What are the different cell types in nervous tissue?
- neuron
- glial cells
- microglial cells - immune function
- astrocyte - support, repair, homeostasis
- ependymal - production and flow of CSF, brain metabolism, waste clearance
What are the different types of glial cell?
- Oligodendrocytes - produce myelin sheath in CNS
- Schwann cells - form myelin sheath in PNS
Where is muscle tissue found?
- attached to skeleton
- blood vessels, GI tract, bladder, uterus, reproductive tracts, eye, hair on skin
- myocardial layer of heart wall
What are the functions of muscle tissue?
- contraction
- produce body movement
- heat generation (shivering)
What are the different types of muscle tissue?
- Skeletal muscle
- Smooth muscle
- Cardiac muscle
Describe skeletal muscle
- voluntary contraction
- striated appearance
- attached to skeleton
Describe smooth muscle
- involuntary contraction
- non-striated
- blood vessels, GI tract, bladder, uterus and reproductive tract, eye, hairs on skin
- autonomic control
Describe cardiac muscle
- involuntary contraction
- heart contractions
- autonomic control
Where is connective tissue found?
- component of all major tissues
- most abundant type in body
What is the function of connective tissue?
- Supportive tissue (basal lamina, bundles of nerves and muscle fibres, outer layer of blood vessel, space between organs)
- musculoskeletal system (bone, cartilage, tendons, ligaments
- fat storage and deposition
- some immune function
What cell types are in the general structure of connective tissue?
- fibroblasts - produce fibres
- adipocytes - store fat
- osteoblasts - build bone
- immune cells
What is the general structure of connective tissue?
- cells create fibres and matrix to form extracellular material around themselves
- most fibres are collagen and elastic fibres
- extracellular mix may be solid (bone), gel-like, or liquid
- minimal blood supply
Give 7 examples of connective tissue
- ligaments and tendons - dense fibrous tissue
- adipose tissue - fat cells
- areolar tissue - loose connective tissue (skin dermis)
- bone
- cartilage
- lymphoid tissue
- blood
What are the properties of cartilage?
- great compressive and tensile strength
- not as strong as bone, but more resilient and elastic
- smooth - can give covering for bones to reduce friction
What are the 3 types of catilage?
- Hyaline cartilage
- Fibrocartilage
- Elastic cartilage
What are the features of hyaline cartilage?
- smooth, glassy, blue/white
- widely distributed
- covers bone at end for low friction
- used in synovial joints
What are the features of fibrocartilage?
collagen fibres cushion between bones and vertebral discs
What are the features of elastic cartilage?
- many elastin fibres in extracellular matrix
- lots of flexibility
- larynx, epiglottis, nose, outer ear
What are the functions of bone?
- Support and leverage
- Protection
- Store of calcium
- Houses bone marrow - source of red blood cells
What is the general composition of bone?
- Extracellular matrix is main component
- Extracellular matrix is made of collagen to give strength and resilience
- Inorganic crystals of calcium hydroxyapatite is deposited in the matrix (calcification) to give hardness and rigidity
What are the different types of bone?
- Compact bone (cortical bone)
- Spongy bone (trabecular bone, cancellous bone)
What is compact bone?
- The outer layer of bones
- Dense and hard
What is spongy bone?
- Inner area of bone
- Has trabiculae (spicules, bony spikes) and airspaces
- Provides maximum strength with minimum weight
- Spaces filled with red or yellow bone marrow
What are the two ways bones can be formed?
- endochondral ossification
- intramembranous ossification
How does endochondral ossification happen?
- cartilage template is formed first and then gradually replaced by bone
- growth can only occur at the growth plates
What bones are formed by intramembranous ossification?
- Cranial vault
- Facial skeleton
- Clavicle
What are the different types of cells in bone?
- Osteocytes
- Osteoclasts
- Osteoblasts
- Osteogenic cell
What do osteocytes do?
Maintenance
What do osteoclasts do?
Bone reabsorption (breaking down)
What do osteoblasts do?
Bone forming
What do osteogenic cells do?
They are stem cells
What are the types of joints?
Synovial and non-synovial
What are features of synovial joints?
- freely mobile
- articular surfaces (move over each other) covered with hyaline/articular cartilage
- lubricated by synovial fluid produced by synovial membrane
- surrounded by capsule and ligaments
- innervated for proprioception
- vary in stability and mobility
What is proprioception?
Ability to detect position and movement from innervation
What are features of non-synovial joints?
- slight/no movement
- bones are connected by fibrocartilage or fibrous tissue
