Tissues Flashcards
Coverings and linings within and outside the body wall.
Functions: Physical protection, control permeability, provide sensation, produce specialized secretions (glands).
Characteristics: Cells bound closely together. Organelles unevenly distributed (found mostly in basal layer - Apical layer mostly cytoplasm), Base bound to thin basal lamina (basement membrane), Bank of stem cells rapidly divide, replace damaged cells at very high rate.
Epithelial
Provides locomotion and heat. Provides form. Regulates blood pressure. Classified by type, location, innervation.
Muscular
Obtains, processes, and responds to sensory information.
Includes neurons and glial (support) cells for the brain.
Composed of cell body with organelles, dendrites (receive signals), axon (send signals), and myelin sheath.
Communicate with other cells via synapse.
Nervous
Binds and supports the body structure. Includes blood. Formal definition: cells embedded in a proteinaceous matrix, mesodermal in origin (due to the extracellular matrix).
Connective
What is the classification of muscular tissue by TYPES
Striated (organized in distinct bundles), Smooth (no obvious organization), Cardiac (bundle pattern unique to the heart and not innervated).
What is the classification of muscle tissue by LOCATION?
Somatic (attached to the skeleton or body wall), Visceral (attached to internal structures).
What is the classification of muscle tissue by INNERVATION?
Voluntary (somatic nervous system), Involuntary (autonomic/visceral nervous system).
Voluntary, striated, multi-nucleated, incapable of division (new fibres produced by satellite/stem cells), growth by hypertrophy (cells increase in size).
Skeletal Muscle
Muscle Fibre Types
Type I (Oxidative), Type IIA (Oxidative/Glycolytic), Type IIX (Glycolytic).
Slow-twitch (10-30Hz)
High resistance to fatigue
High in mitochondria
High in oxidative capacity
High capillary density
High myoglobin content
Low glycogen storage
Type I Muscle Fibre
Fast-twitch (30-60Hz)
Moderate/high resistance to fatigue
High in mitochondria
Medium/High oxidative capacity
Medium capillary density
High myoglobin content
High glycogen storage
Type IIA Muscle Fibre
Really fast-twitch (60-90Hz)
Low resistance to fatigue
Low in mitochondria
Low oxidative capacity
Low capillary density
Low myoglobin content
High glycogen storage
Type IIB (IIX)
Involuntary, non-striated, single nucleus, muscular wall of stomach and viscera, lining of arteries.
Can find in sphincter/dilator pupil.
Smooth Muscle
Involuntary, single nucleus usually, forms myocardium of heart, intercalated disks, unique whorl-shape. Not innervated.
Cardiac Muscle
Process:
Electrochemical gradient between cell at rest and surrounding environment. Cell slightly negative. Discharge called an ACTION POTENTIAL.
Nerve cells do not directly contact one another, cannot transmit electrical signal, instead they release chemical signals (neurotransmitters) into space between cells.
Synapse
