L1a - Tissues & Systems (1) Flashcards
What is an organum?
An instrument or tool
Define ‘Viscus’ / ‘Viscera’ (plural).
Two or more tissues which together perform a specialised function.
How many organ systems are there?
11
What are the 2 different types of tissue?
- Main tissue
- Sporadic tissue
Name the 11 organ systems.
- Integumentary System
- Musculoskeletal System
- Nervous System
- Endocrine System
- Cardiovascular System
- Lymphatic System
- Respiratory System
- Urinary System
- Digestive System
- Reproductive System
- Immune System
Describe the characteristics of tissues.
- Group of similar cells
- Similar embryological origin
- Specialised for a particular function
What are cells separated by?
A matrix
What is a matrix?
Non-living, intercellular material produced by cells
What is the study of tissues called?
Histology
Name the 4 main types of tissues.
- Epithelial Tissue
- Connective Tissue
- Muscle Tissue
- Nervous Tissue
Describe the role of epithelial tissue.
- Protection
- Lining
- Secretion
- Filtration
- Absorption
Describe the role of connective tissue.
- Protection
- Support and binding
- Energy storage
- Transport
- Immunity
Describe the role of muscle tissue.
- Locomotion
- Movement of food
- Beating of the heart
Describe the role of nervous tissue.
- Transmission of impulses to achieve communication, coordination and control
What are epithelial cells closely packed into?
Single continuous sheets or in multiple layers
What do junctions between epithelial cells ensure?
Attachment to neighbouring cells
How can substances pass through epithelial cell layers?
- Diffusion
- Transportation
Epithelial cells are polar. Which 2 surfaces does this result in?
- Apical surface (top)
- Basal surface (bottom)
Describe the apical surface of epithelial cells.
- Exposed to a body cavity
- Line an organ
- Exposed to exterior
- Can contain microvilli or cilia
Describe the basal surface of epithelial cells.
- Attached to a basement membrane secreted by the cells
- Adheres the tissue firmly to nearby connective tissue
What does it mean that epithelia are avascular?
Blood vessels tend to run under epithelial layers, but do not go through them; so rely on diffusion for oxygen and nutrients, and to remove waste.
Capillaries usually found below basement membrane.
Epithelia usually have a _____ supply.
Epithelia usually have a nerve supply.
Epithelia are usually able to __________ via _______ as they often suffer wear and tear.
Epithelia are usually able to regenerate via mitosis as they often suffer wear and tear.
In addition to protection, lining, secretion, filtration and absorption, what else does epithelial tissue function include?
- Lubrication
- Digestion
- Excretion
- Transportation
- Sensory reception and reproduction
What are the three classifications of epithelial cells based on layers?
- Simple (single layer of cells)
- Stratified (multiple layers of cells)
- Pseudo-stratified (look like multiple layers of cells, but only a single layer in reality)
Provide an example of where you may see a simple epithelial cell. Why would this cell type be present here?
- Alveoli of lungs
- Endothelium of blood vessels
- Require fast, seamless diffusion of substances
State the 4 different shapes of epithelial cells.
- Squamous
- Cuboidal
- Columnar
- Transitional
Describe the characteristics of squamous epithelial cells.
- Flat cells
- Oval nuclei
- Thin for diffusion
Describe the characteristics of cuboidal epithelial cells.
- Cube like cells
- Central nuclei
- Can product secretions
- Can participate in absorption
Describe the characteristics of columnar epithelial cells.
- Column shaped cells
- Variable nuclei
- Protect underlying tissue
- Involved in secretion / absorption
Describe the characteristics of transitional epithelial cells.
- Variable shape
- Can change from flat to columnar in response to distension, expansion or movement of body parts
Provide an example of where you may see a stratified epithelial cell. Why would this cell type be present here?
- Skin
- Oesophagus
- Areas exposed to chemical or physical stresses
- Require multiple layers of protection
Provide an example of where you may see a pseudo stratified epithelial cell. Why would this cell type be present here?
- Upper airways
- Trachea
- Bronchi
- Appearance is primarily due to variations in shape and position of the nuclei of its different cell types
Describe a simple epithelium.
Single layer allowing diffusion osmosis filtration secretion and absorption to take place
Describe a stratified epithelium.
Multiple layers of cells protecting deep layers from wear and tear
Describe a pseudo stratified epithelium.
Single layer of cells that appears to consist of multiple layers as they have nuclei at different levels - not all cells reach the surface
Some cells are ciliated or secrete mucus (goblet cells)
What is an integumentum?
A covering
What does the integumentary system comprise?
The skin and its derived organs (hair, glands, nails and nerve endings)
What is the study of skin known as?
Dermatology
The skin is a very large organ. Approximately how many m^2 is the integumentary system?
1.5 - 2 m^2
The skin is a very large organ. Approximately how many mm thick is the integumentary system?
2 - 3mm
The skin is a very large organ. How much does the integumentary system weigh on average?
5 kgs
The integumentary system is the largest _____ organ in the body.
The integumentary system is the largest sense organ in the body.
What are the functions of the integumentary system?
- Protection (external body covering)
- Sensation (temperature regulation)
- Excretion (protection, immunity and resistance)
- Blood Reservoir (synthesis of vitamin D)
What types of cells make up the epidermis?
Stratified squamous
What makes up the dermis?
Primarily, dense irregular connective tissue
What makes up the subcutaneous layer?
Areolar and adipose tissue
Is the subcutaneous layer part of the integumentary system?
No, but it is closely involved with the structure and function of skin.