Lecture 14 Flashcards
What happens during development?
Stem and progenitor cells differentiate, specialise and unite to form tissues. Tissues combine to form organs and organs work together in organ systems
As cells differentiate, what are the 3 primary germ layers that they organise themselves as?
Mesoderm, ectoderm and endoderm
What is a tissue?
A group of cells that share a common embryonic origin, which form a specific architecture and cell specialisation to perform and function and carry out specialised activities
e.g. Hard (bone, liquid (blood), etc
Histology?
Science that deals with the study of tissue
Epithelial tissue?
Covers body surfaces and lines hollow organs, body cavities, ducts, and forms glands
Connective tissue?
Protects, supports and binds organs. Stores energy as fat and provides immunity
Muscle tissue?
Generates the physical force needed to make body structures move and generate body heat
Nervous tissue?
Detect changes in body and responds by generating nerve impulses
What germ layer(s) are the epithelial tissue developed from?
All three (endoderm, ectoderm and mesoderm)
What germ layer is the connective tissue developed from?
Mesoderm layer
What germ layer is the muscle tissue developed from?
Mostly the mesoderm layer
What germ layer is the nervous tissue developed from?
The ectoderm layer
Epithelial tissue structure?
Consist of cells arranged in continuous sheets, in either single or multiple layers:
- Closely packed and held highly together
- Covering and lining of the body
- One free surface
Epithelial tissue structure?
Consist of cells arranged in continuous sheets, in either single or multiple layers:
- Closely packed and held tightly together by cell to cell adhesions(tight junctions/gap junctions)
- Cover linings within the body
- Have one free surface that either empties into a body cavity or the environment
What basic biological principle do epithelial tissues illustrate?
Structure closely correlates with function
Serous membrane?
A thin membrane made from epithelial tissue that lines the internal body cavities and organs such as the heart, lungs, and abdominal cavity
Mucous membrane?
A membrane that lines various cavities in the body and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue
What are the 3 different types of surface on an epithelial cell?
Apical (free) surface:
- Faces the body surface, body cavity, lumen, or duct
Lateral surface:
- Faces adjacent cells
Basal surface:
- Opposite of apical layer and adhere to extracellular materials
What are the 3 different types of surface on an epithelial cell?
Apical (free) surface:
- Faces the body surface, body cavity, lumen, or duct
- Absorbance/secretion functions
Lateral surface:
- Faces adjacent cells
- Allows cells to tightly pack together and adhere
Basal surface:
- Opposite of apical layer and adhere to extracellular materials
- Attaches epithelial layer to the underlying connective tissue, providing a continuous piece of tissue
What do epithelial cells rest on?
A basement membrane
- Thin double layer that serves as the point of attachment and support for overlying epithelial tissue
What does the basement membrane consist of?
- Basal lamina
- Closer to and secreted by epithelial cells
- Contains collagen, laminin, glycoproteins and proteoglycans - Reticular lamina
- Closer to the underlying connective tissue
- Contains collagen secreted by the connective tissue
What are different features of epithelial tissue?
- own nerve supply
- lacks vasculature (blood supply)
- blood vessels in the connective tissue underneath bring nutrients and eliminate waste
- high rate of cell division for renewal and repair
- numerous roles in body (protection and filtration)
What are the two main types if epithelial tissue?
- Covering and lining epithelium (membranous)
- Outer covering of skin and some internal organs - Glandular epithelium
- Secreting portion of glands (thyroid, adrenal and sweat glands)
3 types of membranous epithelium?
- Stratified squamous
- Protective barrier
- Made of keratinocytes which pick up sacs of keratin, forming plaques and moving from the basal layer to the surface as they mature - Simple columnar
- Single layer of cells that are arranged into a tightly packed column formation
- Microvilli structure
- For absorption and secretion - Simple cuboidal
- Secretion into cells
- Ease movement
- Simple cuboidal structure
2 types of glandular epithelium?
- Exocrine
- Secrete onto an epithelial surface
- Unicellular glands secrete mucus
- Multicellular glands secrete sweat - Endocrine glands
- Release hormones into interstitial fluid or blood
- Don’t have ducts
What are the two components of connective tissue?
- Cells
- Extracellular material (matrix)
What are two types of connective tissue?
- Connective tissue proper
- Specialised connective tissue
What is the main component of connective tissue?
Cells
What are the different connective tissue cells?
Fibroblasts, adipocytes, mast cells, white blood cells, macrophages and plasma cells
Fibroblasts?
Secrete fibres and components of ground substance
Adipocytes (fat cells)?
Store triglycerides (fat)
Mast cells?
Produce histamine (for allergies)
White blood cells?
- Immune response
- Neutrophil and eosinophils
Macrophages?
Engulf bacteria and cellular debris by phagocytosis
Plasma cells?
Secrete antibodies
What is the extracellular matrix composed of?
- Ground substance
- Supports and binds cells, stores water, and allows exchange between blood and cells - Fibres
Two types of connective tissue proper?
- Dense connective tissue
- Densely packed fibres
- Interspersed with cells in between - Loose connective tissue
- Loose network of fibres
- Cells in between
E.g. areolar
Function of connective tissue proper?
Structural component of organs
Function of specialised connective tissues?
Perform specific function essential to homeostasis
What are three types of specialised connective tissue?
Cartilage, bone and blood
Two types of dense connective tissue?
- Regular
- Bundles of fibres in a parallel line for strength
- Tendons and ligaments - Irregular
- Fibres irregularly arranged
- Dermis of skin and heart
- Found where pulling forces are exerted in many directions - Elastic
- Contain branching elastic fibres
- Strong and can recoil to original shape after stretching
- Lung tissue and arteries
