types of tissue Flashcards
what is a tissue ?
Similarly specialised cells, in close proximity, that are organised to perform one or more specific function
what are the four main types of tissues and what are there basic functions ?
4 main tissue types in the human body:
* Epithelial: covers body surface and lines body cavities
* Connective: binds and supports other tissue types
* Muscular: contracts to initiate movement
* Nervous: receives, interprets and sends signals
describe epithelial cells function
- Highly cellular tissue that forms the covering of all body surfaces
- Found in outer layer of skin, lining of body cavities, blood and lymph vessels
- Protects exposed and internal surfaces from abrasion, dehydration and destruction by chemical or biological agents
- They can proliferate to produce new cells when cells become damaged or worn
Epithelial Tissue
what are the epithelial tissue cell shapes ?
Sqaumous – flattened cells whose width is greater than their height
Cuboidal – cells appear as high as they are wide; spherical nuclei centrally positioned
Columnar – cells whose height is greater than their width; oval nuclei positioned at the base of cells
if epithelial tissue is one cell thick, what would it be classed as ?
simple
if epithelial tissue is two or more layer of cells, what is it classed as ?
stratified
what are function of epithelial cells ?
- Protection
- Epithelial cells from the skin protect underlying tissue from mechanical injury, harmful chemicals,invading bacteria and
from excessive loss of water - Sensation
- Sensory stimuli penetrate specialised epithelial cells. Specialised epithelial tissue containing sensory nerve endings is found in the skin, eyes, ears, nose and on the tongue
- Secretion
- In glands, epithelial tissue is specialised to secrete specific chemical substances such as enzymes,hormones and lubricating fluids
- Absorption
- Certain epithelial cells lining the small intestine absorb nutrients from the digestion of food
- Excretion
- Epithelial tissues in the kidney excrete waste products from the body and reabsorb needed materials from
the urine. Sweat is also excreted from the body by epithelial cells in the sweat glands - Diffusion
- Simple epithelium promotes the diffusion of gases, liquids and nutrients. Because they form such a thin
lining, they are ideal for the diffusion of gases (eg. walls of capillaries and lungs) - Cleaning
- Ciliated epithelium assists in removing dust particles and foreign bodies which have entered the air passages
- Reduces Friction
- The smooth, tightly-interlocking, epithelial cells that line the entire circulatory system reduce friction
between the blood and the walls of the blood vessels
give examples of epithelial tissue
bowman’s capsule ,ileum , oesophagus
what are the functions of connective tissue ?
- Protection of organs
- Provision of structural framework for the body
- Connection of body tissues
- Connection of epithelial tissues to muscle
- Nutritional support to epithelium
- Repair of body tissues
what is connective tissue ?
- Most abundant tissue within the body
- Consists of cells and an extracellular matrix (ground substance and protein fibres)
- Essentially connects the epithelial tissue to the rest of the body
- Not normally exposed to the outside environment e.g., cartilage, tendons, fascia, blood
what is muscle tissue ?
Specialised to contract and produce movement
* Contains highly organised bundles of cells
* There are three types of muscle tissue; skeletal,smooth and cardiac
describe skeletal muscle
- Primarily involved in locomotion
- Also involved in maintaining posture
- Under voluntary control
- Cells are large, cylindrical and elongated
- Often known as striated muscle due to the appearance of contractile proteins
- Average adult male - 42%, average adult female - 36% skeletal muscle (total body weight)
what do skeletal muscle cells look like?
look at lecture
describe smooth muscle?
- Lines structures including the stomach, intestines, and blood vessels
- Primary function is to influence movement of material into, out of, and within the body
- Involuntary muscle type
- Non-striated – different arrangement of muscle cells compared to skeletal muscle
what does smooth muscle look like ?
look at lecture slides for this
