Tissues in the Human Body Flashcards
What are the 4 types of tissue classes?
Nervous tissue
Muscular tissue
Epithelial tissue
Connective tissue
What are epithelial tissues?
A sheet of cells that covers a body surface or lines a body cavity
2 types: simple and stratified
What are the main functions of epithelial tissues?
Filtration and secretion
Protection
Absorption of nutrients
Sensation/touch
What are the 5 special characteristics of epithelium?
- Polarity
- Specialised Contacts - (cells fit close together, adjacent cells are bound together by lateral contacts)
- Supported by connective tissue
- Avascular but innervated - (contains no blood vessels but is supplied by nerve fibres)
- Regeneration
What are the 3 types of simple epithelial tissues?
Squamous
Cuboidal
Columnar
What are the differences between simple epithelium and stratified epithelium?
Simple ET has one layer of cells
Simple ET have different shape nuclei than stratified tissues
Simple ET have no blood vessels and have basal specialisation
Describe simple squamous epithelium.
Single layer of flattened cells
Has sparse cytoplasm
Thin, permeable helps with filtration by rapid diffusion.
Describe simple cuboidal epithelium.
Single layer of cube-like cells with spherical nucleus
Secretes and absorbs nutrients
Describe simple columnar epithelium.
Single layer of tall cells, round/oval nuclei
Contain microvilli and goblet cells
Absorption and secretion
What are connective tissues?
Found everywhere in the body, but amounts in particular organs vary
(skin consists primarily of connective tissue where brain contain very little)
What are the 4 main types of connective tissue?
Connective tissue proper
Cartilage
Bone
Blood
What are the main functions of connective tissue?
Binding of organs
Support & movement
Physical & immune protection
Storage & transport
What are the 3 main types of connective tissue proper?
- Areolar connective tissue (loose)
- Dense connective tissue
- Adipose connective tissue
What are the functions of areolar connective tissue?
Supports and binding other tissues
Holds body fluids
Defends against protection
Stores nutrients as fats
What are the 3 main types of dense connective tissue?
Dense regular
Dense irregular
Elastic
What are the functions of adipose connective tissue?
Acts as a shock absorber
Stores a great amount of nutrients
‘fatty tissues’ so provides insulation and energy storage
What is cartilage?
A tough but flexible type of connective tissue (shares properties of bone)
Cartilage matrix made up of 80% water, enabling it to rebound after compression
What are the 3 variants of cartilage?
Hyaline cartilage
Elastic cartilage
Fibrocartilage
(each dominated by a different fibre)
Describe hyaline cartilage.
Most abundant cartilage type. Contains collagen fibres.
Provides support with some pliability, covers end of long bones providing springy pads that absorb compression at joints.
Describe elastic cartilage.
Almost identical to hyaline, however there are more elastic fibres.
Found where strength and stretchability are needed.
Describe fibrocartilage.
Has rows of chondrocytes and alternate rows of thick collagen
Found where strong support and ability to withstand pressure is required.
Describe what bone is.
Due to its rock-like hardness, bone supports and protects body structures
Osteoblasts produce organic portion of bone’s matrix and has a lot of collagen fibres
Describe what blood is.
A type of atypical connective tissue - it does not connect things or support.
The ‘fibre’ are soluble protein molecules that precipitate. Transport vehicle for cardiovascular system.
Why is blood considered an atypical connective tissue?
Blood develops from mesenchyme and consists of blood cells, surrounded by a non-living fluid matrix called blood plasma
What are nervous tissues?
Main component of the nervous system and regulates and controls body functions.
What are the functions of nervous tissues?
Responds to stimuli
Transmits electrical impulses over substantial distances within the body
What are muscle tissues?
Muscle tissues are highly cellular, well vascularised tissues that are responsible for most body movements.
Processes myofilaments (actin and myosin filaments)
What are the 3 types of muscle tissues?
- Skeletal muscle
- Cardiac muscle
- Smooth muscle
Describe skeletal muscle tissue.
Form the flesh of the body.
Contracts, pulling on bones or skin, causing body movements.
Under conscious control, called a voluntary muscle.
Describe cardiac muscle.
Found only in the walls of the heart.
Contracts to help propel blood throughout the blood vessels to all parts of the body.
Compare skeletal muscle tissues and cardiac muscle tissue.
Both are striated. However, they differ structurally in cardiac cells…
Are generally uninucleate
Are branching cells that fit together tightly at intercalated discs
Describe smooth muscle
Found in the walls of hollow organs other than the heart.
Acts to squeeze substances through these organs by alternately contracting and relaxing.
