Cellular Physiology Flashcards
4 classes of cells in the body
- > muscle cells
- > nerve cells
- > connective tissue/cells
- > epithilial cells
*ALL ORGANS ARE MADE UP OF ALL 4 CLASSES BUT HAVE DIFFERENT RATIOS OF EACH*
classes of MUSCLE cells and what do they control
- Skeletal muscles (motion)
- Smooth muscles (controls fluid flow)
- Cardiac muscles (controls bloodflow)
Which two types of muscle cells are the most similar
skeletal and cardiac cells are the most similar of the muscle cells; smooth muscle cells are more unique than the other two
Characteristics of skeletal muscles
- > also know as striated muscle (because or parallel arragement of filaments)
- > cylindical, multi-nucleated
Name the layers of A muscle
Outer
Epimysium
Perimysium (wraps fasicle)
Endomysium (wraps muscle fibre/cell)
Inner
Sarcomeres
individual units within a muscle fibre/cell which are composed of various fibres and proteins that play a role in contraction and the regulation of contraction
Sub-classes of skeletal muscle fibres
- Slow Twitch
- > slow activation/contraction and are relatively resistant to fatigue - Fast Twitch
- > fast activation/contraction and not as resistant to fatigue
Metabolic sub-classes of skeletal muscle fibres
*muscles are made up of various sub-classes*
- Slow Oxidative (SO Fibres)
- > slow twitch; relies on O2 - Fast Glycolitic (FG Fibres)
- > fast twitch; can produce ATP anaerobically - Fast Oxidative-Glycolytic (FOG Fibres)
- > fast twitch; O2 requiring but can also function anaerobically
Which muscles produce more ATP… Oxidative pathways or Glycolitic
Oxidative Pathways (mitochondria needs O2)
Pathway of skeletal muscle activation
Activation/Contraction of smooth muscle is through what?
- Spontaneous electrical activity initiated by pacemaker cells
the SEA gives a baseline level of contraction/relaxation as it plays a role in paristalsis and segmentation
- Nerves and hormones
- Local factors
pacemaker cells
*SA NODES*
create these rhythmic impulses, setting the pace for blood pumping; they directly control heart rate
Explain the innervation of smooth muscle by the autonomous nervous system
sympathetic nervous system
- > solely innervates Vascular smooth muscle
- > there is always some baseline level of stimulation of vascular smooth muscle
parasympathetic nervous system
- > healily innervaes the GI smooth muscle
Explain how local factors work to make changes within the body
LF’s are released by a cell (usually epithilial) and affect the smooth muscle in the region of release
- > many LF’s are responsible for vascular smooth msucle relaxation (+ some contraction)
smooth muscle activation/contraction pathways
- Single-unit smooth muscle
- > all cells/fibres work together with a single activating event - Multi-unit smooth muscle
- > each cell/fibre must be activated seperately
Differences between cardiac and skeletal muscles
- > cardiac muscle cells are spearated by intercalcated discs (desmosomes)
- > cardiac muscles only have the capacity to contract with O2 (oxidative phosphorilation) so it needs more mitochondria as that is where OP occurs
- > cardiac fibres are not arraged in a tight, parallel orientation
How are SA Nodes innervated
SA node are innervated by the Autonomous nervous system
(sympathetic raises heartrate parasympathetic lowers it)
- > this occurs due to circulating hormones that bind to receptors on cardiac muscle cells
characteristics of general epithilial cells
- > located at the surface or line the walls of tubular and hollow structures
- > rest on non-cellular material (basement membrane)
- > regulate the movement of molecules in and out of organs, tissues, and body fluids
- > epithelial cell membranes have different functions depending on which side of the epi.cell the membrane lies
membranes of general epithilium
luminal membrane
- > part of the epi.membrane that faces the inside of the organ/tube
Basolateral (outter)
- > the part of the epi.mem. that faces the basement membrane, which is the outer surface of the organ/tube
these two membranes work together to determine the movement of substances in/out of fluid in lumen
Paracellular transport vs Transcellular transport
PT
- > “leaky” epi. allows small molecules to pass between cells
TT
- > tight junctions between epithelium forces movement to occur through the basolateral membrane, into the epi. cell and into the hollow tube/organ (this process helps regulate)
Classification of glands
Exocrine glands
- > secrete through ducts to the outside of the body (i.e. sebacous glands)
Endocrine glands
- > secretes directly into the blood (usually systemic circulation beu sometime locally)
componants of extracellular matrix
collagen fibres, elastin fibres, reticular fibres
mostly proper connective issue
componants of extracellular fluid
Extracellular fluid = interstitial fluid + plasma
Interstitial fluid is the fluid that surrounds all cells, tissues and organs
plasma is the fluid portion of blood
Intracellular vs Extracellular fluid vs interstitial fluid
fluid inside vs outside fluid of the cell that differs in terms of ions molecular content
interstitial fluid and plasma make up extracellular fluid