Lecture 2 Tissue Types & Structures 1 Flashcards
What are the 4 basic tissue types?
- Epithelial
- Connective
- Muscle tissue
- Nervous tissue
What is epithelial cells origin?
Inside
Endoderm
Origin of nerve tissue
Outside
Ectoderm
Origin of connective and muscle tissue
Middle
Mesoderm
What are cell junctions & name the 5 different types?
Join cells in tissue - contact points between plasma membrane of tissue cells
- Tight
- Adherens
- Desmosome
- Hemidesmosome
- Gap
Tight junction structure & function
- Adjacent plasma membranes
- intercellular space
- strands of transmembrane protein
Form seals
Adherens junction structure (5) & function
-adjacent plasma membranes
-microfilament (actin)
-plaque
-transmembrane glycoprotein (cadherin)
- intercellular space
-adhesion belt
Structural strength
Desmosome (5)
- adjacent plasma membranes
-intracellular space
-plaque - transmembrane glycoprotein (cadherin)
-intermediate filament (keratin)
Withstand intense mechanical stress
Hemidesmosome
- intermediate filament(keratin)
- plaque
- transmembrane glycoprotein (integrin) in extracellular space
- plasma membrane
- Basement membrane
Anchor cells to extracellular matrix
Gap junction
- adjacent plasma membranes
- connexons (composed of connexins) (12 in total 6 on each side)
- gap between cells
Gaps for rapid exchange
Functions of nervous tissue
Detects internal & external changes in conditions & acts to maintain homeostasis
What are 2 main cell types of nervous tissue & what do they do?
- Neurons - generate & conduct nerve impulses
- cell body - nucleus & other organelles
- dendrites - recieve signals
- axons - conduction over long distance - Neuroglia - non-conducting
Insulate, support & protect neurons
What are the 3 different types of neuronal cells?
- Multipolar neuron - has many processes extending from cell body
- Bipolar neuron- has 2 processes extending from cell body
- Unipolar neuron - has 1 process extending from cell body
What can the central nervous system (CNS) be divided into?
Motor output ( somatic & autonomic)
Sensory input
What is the human brain responsible for? (4)
- Cognition
- learning
- memory
- somehow enables us to be ‘self-aware’
Function of muscle tissue
Generates physical force for movement
What are the 3 types of muscle tissue?
- Skeletal muscle
- Smooth muscle
- Cardiac muscle
Structure of skeleton muscle (5)
- Long, cylindrical cells containing peripheral nuclei
- Myofilament arrangement give tissue a striated appearance
- Attached to bones of skeleton
- Parallel fibres
- Voluntary - conscious control (somatic nervous system)
Structure of Cardiac muscle (4)
- Found only in cell walls of heart
- Central nuclei
- Cells joined end-to-end intercalated discs
- Striated and involuntary
Structure of Smooth muscle (4)
- No striations
- Cells thick in middle & taper at each end
- Central nucleus
- Found in walls of hollow structures (blood vessels, lung airways, intestines…)
Epithelial tissue general points (5)
- Forms continuous sheets
- Functions: covers body surfaces, lines hollow organs, forms glands…
- Avascular (few or no blood vessels)
- Innervated (nerves between epithelium tissue)
- Generally has a high proliferation potential (high rate of cell division)
Function & location of Simple squamous
Function: includes filtration or exchange via diffusion
Location:
includes kidney,
capillaries,
alveoli,
lymphatic vessels
Function & location of Simple Cuboidal
Function: secretion & absorption
Location:
includes kidney tubules,
small glands
Function & location of Non-Ciliated Simple Columnar
Function: absorption & secretion
Location:
digestive tract,
gall bladder,
some excretory glands
Function & location of Ciliated Simple Columnar epithelium
Function: moves mucous in lungs also eggs down fallopian tubules
Location:
Upper respiratory tract
Fallopian tubes…
Function & location of Stratified Squamous epithelium
Function: protection from abrasion
Location:
Oesophagus (non-keratinised)
Epidermis (keratinised)
Function & location of stratified cuboidal epithelium
Function: protection, secretion absorption
Location:
Large ducts of glands
Function & location of stratified columnar epithelium
Function: protection, secretion
Location: examples include
Urethra
Ducts of some glands e.g. salivary gland
Function & location of Transitional Epithelium
Function: permits distension
Location: urinary bladder
Ureters