Body Systems L4 Flashcards
What is a tissue?
Group of similar cells -> specific function.
List the types of basic tissues.
Epithelia
Connective
Muscle
Nervous
What is the function of the epithelial tissue?
- Covers inner & outer surfaces
- Line cavities & tubes eg. Hollow organs, airways, blood vessels
- Glands
What characteristics does epithelial tissue have?
-Attachment
-Avascularity -> no blood vessels run through it
-Regenerates
-Polarity (apical -> faces surface & basal -> bottom)
-Closely packed cells supported by basement mem
How is epithelial tissue classified?
- Classification based on no of cells and shape in most superficial layer
1. No. of cell layers
2. Shape
What are the two classifications for cell layers of epithelial tissue?
> Simple -> one layer
> Stratified -> more than one layer
What are the classifications of shapes used in epithelial tissues?
> Squamous (flat)
Cuboidal (cube)
Columnar (rectangle)
List examples of epithelial tissue.
- Simple squamous
- Non-keratinised stratified squamous
- Keratinised stratified Squamous
- Simple cuboidal epithelium
- Simple columnar epithelium
What is the function of and where are simple squamous tissue found?
Exchange of nutrients & gases
-> Blood vessels & alveoli
What is the function of and where are non-keratinised stratified squamous tissue found?
Protection
-> Oral cavity & oesophagus
What is the function of and where are keratinised stratified squamous tissue found?
Waterproof protection/barrier
-> Skin
What is the function of and where are simple cuboidal epithelium found?
Secretion & absorption
-> Glands & kidney tubules
What is the function of and where are simple columnar epithelium found?
Absorption & secretion
-> Gastrointestinal tract
- -> also have microvilli
- > Enabling absorption of nutrients.
What is the function of and where are simple pseudostratified ciliated epithelium with goblet cells found?
Mucociliary escalator
-> produce mucous -> particles inhaled -> trapped in mucous.
-> Cilia moves mucous upwards to back of throat for swallowing.
-> Trachea & large respiratory airways.
-> Also has cilia & goblet cells.
Trachea appears stratified -> some cells don’t reach free surface -> All touch
basement mem.
What are intercellular junctions?
- Specialised areas of cell mem -> bind cells to one another.
List the types of intercellular junction
- Desosomes
- Hemidesosomes
- Tight junctions
- Gap junctions
What is the purpose of desosomes?
Strong
Join adjacent cells
Resist stretching & twisting
What is the purpose of hemidesosomes?
Stabilising
Attach cells to basement mem
Anchor to underlying tissue
What is the purpose of tight junctions? Give an example.
Binds adjacent cells -> interlocking proteins
Prevents passage of water & solutes between cells
Found on Apical side of cells
Eg. Digestive tract -> Prevents digestive fluids passing between epithelial cells.
What is the purpose of gap junctions?
Interlocking mem proteins (connexons) bind cells together
Connexons – central pore enabling movement of small molecules & ions between cells
Cardiac muscle
What are the functions of connective tissue?
- Structural framework for body
- Supports surrounds & interconnects tissues
- Protects delicate organs
- Transports fluids & dissolved materials
- Stores energy reserves
- Defence -> microorganisms
What is connective tissue composed of?
- Cells within Extracellular matrix
What types of cells comprise the extracellular matrix of connective tissue?
> Fibroblasts -> Main cell type -> Synthesises extracellular matrix
Apipocytes
Macrophage cells
Mast cells
What is the extracellular matrix of connective tissue composed of?
Ground substance Tissue (extracellular fluid) Fibres: ->Collagen ->Reticular ->Elastic
Name the classifications of connective tissue.
- Specialised connective tissue
2. Connective tissue proper
Name the types of specialised connective tissue
- Blood
- Bone
- Cartilage
How is connective tissue proper classified? List the different types.
Classified according to type, arrangement & abundance of fibres, cells & ground substance
- Loose areolar/irregular
- Dense irregular connective
- Dense regular
Describe Loose areolar/irregular tissue
- > Lots -> ground substance
- > Few fibres
- Collagen & Elastic - > Variety of cells
- Fibroblasts, adiposcytes, macrophages (transient)
- > Under epithelium covering & lining body surfaces.
Describe dense irregular connective tissue
- Dense irregular connective tissue:
- > Little ground substance
- > Lots -> collagen fibre bundles -> arranged haphazardly
- >Few cells- Mainly fibroblasts
- > Resists excessive stretching & distension
- > Found in dermis
- Mainly fibroblasts
Describe dense regular connective tissue
- > Little ground substance
- > Lots -> densely packed bundles of collagen fibres -> parallel rows
- > Few cells
- Mainly fibroblast
- > Found in tendons & ligaments.
What is the function of muscle tissue?
Name the types & similarities they share.
- Produces movement -> specialised for contraction
- 3 types – skeletal , smooth & cardiac.
Similarirties - Elongated parallel to axis of contraction
- Numerous mitochondria
-Contractile elements
Describe skeletal muscle
1. Skeletal Moves & stabilises skeleton Forms sphincters in digestive & urinary tracts -> controls urges to pee etc. Involved in respiration - Long cylindrical cells - Striated (striped) - Multinucleated (multiple per cell) - Innervated -> somatic nervous system
Describe smooth muscle
- Smooth
Forms walls of organs, blood vessels & airways
Gastrointestinal movement
Alters diameters -> airways & blood vessels
- Short, fusiform (narrow at ends) cells
- Non striated (not striped)
- Single central nucleus
- Innervated -> autonomic nervous system
Describe cardiac muscle
Heart wall Circulates blood & maintain blood pressure - Branched muscle fibres - Striated (striped) - 1-2 central nuclei - Intercalated discs - Innervated -> autonomic nervous system
What is histology?
Study of tissue -> cellular level.
Give an example of specialised tissue in animals, it’s characteristics & how this is beneficial to the animal.
• Hibernating animals
Large quantity -> multilocular adipose tissue (brown adipose tissue)
Tissue cells >Numerous droplets lipid -> cytoplasm
>Lots -> mitochondria
–>Able to uncouple oxidation from phosphorylation
»_space; Releases heat -> instead -> ATP
»_space;>Incr. heat -> arouses -> hibernation.
Highly vascularised tissue -> even distribution -> heat.
