Functional Organization of cells Flashcards
What is a cell
The smallest basic living unit
What is a tissue
group(s) of cell types and intercellular material that group together to perform specific fxn
I.E. Muscle or Nerve
Organ/Organ System
Aggregate of cells/tissues held together by intra/intercellular support structures
I.E. Kidney, Heart, GI Tract
Basic Tissue Types
Nervous
Epithelial
Muscle
Connective
Nervous Tissue Characteristics
Cell,extracellular matrix, fxn
Cells: Intertwining Elongated
Extracellular Matrix: None
Fxn: Transmision of APs
Epithelial Tissue Characteristics
Cell,extracellular matrix, fxn
Cells: Aggregated Polyhedral
Extracellular Matrix: minimal
Fxn: lining of surface or body cavities; absorption, glandular secretions
Muscle Tissue Characteristics
Cell,extracellular matrix, fxn
Cells: Elongated contractile cells
Extracellular Matrix: Moderate amount
Fxn: Movement
Connective Tissue Characteristics
Cell,extracellular matrix, fxn
Cells: Several types of fixed or wandering cells
Extracellular matrix: Abundant amount; matrix is the basis for fxn of each CT type
Fxn: multiple fxns from structure to immunity
Intracellular Fluid
- 2/3 of total body water
- Primarily a solution of K and organic anions (high K, low NA), CHO, PRO, Lipids, AAs
- Not homogeneous in your body. It represents a conglomeration of fluids from all the different cells.
- Cell membrane/metabolism control cytosol contents
Extracellular Fluid
- 1/3 of total body water
*Primarily a NaCl and NaHCO3 solution.
*Further subdivided into three sub compartments: Interstitial Fluid (ISF)
Plasma
Transcellular Fluid
The 60-40-20 Rule
60 % of body weight is water
40% of body weight is intracellular fluids
20% of body weight is extracellular fluid
Cytoplasm- protoplasm of the cell: intracellular fluid and organelles excluding nuclear material
Interstitial Fluid
Surrounds cells, does not circulate
- makes up 3/4 of ECF
Plasma
Extracellular component of blood; circulates
- makes up 1/4 of ECF
Transcellular Fluids
Outside of normal compartments (~1-2L of fluid
Examples:
-CSF, Synovial fluid, Mucus, digestive juices
Plasmalemma-Phospholipids
Polar region: hydroPHILIC (heads)
Non-polar region: hydroPHOBIC (tails)
Selective permeability: plasmalemma fxn
hydroPHOBIC molecules pass easily;
hydroPHILIC molecules do not
controls whats allowed into internal cellular environment
Physical isolation: plasmalemma fxn
maintenance of internal cell environment
keeps cellular components in protected environment
Immunospecificity: plasmalemma fxn
serves as recognition site for other cells and antibodies
hydrophilic molecules
Water soluble Glucose Ions Urea PRO *Require specific entry route to get into/out of cell
Hydrophobic molecules
Fat soluble O2 CO2 Alcohol Lipids, fats Easily move b/w cytoplasm and extracellular space
Cell Membrane Proportions
Protein: 55% Phospholipids: 25% Cholesterol: 13% Other lipids: 4% CHO: 3%
Cholesterol
Increased amounts of cholesterol=increased viscosity (like jam vs water=thicker)
Allows cell to control fluidity of plasmalemma to faciliate cell mvmt and rigidity
Integral transmembrane proteins
span the lipid bi-layer fxn as a channel or pore, carrier proteins, or cell surface receptors
Channel or pore: membrane proteins
for water, and water soluble substances (ions)
diffuse between the extracellular and intracellular environments
Carrier proteins: membrane proteins
actively transport molecules against the concentration gradient
Transport substances that otherwise could not penetrate and (active transport- against the natural direction of diffusion) enzymes
Cell surface receptor: membrane proteins
identification for cells and antibodies
assist in recognition of self and non-self
Ligand
molecule that binds to a particular receptor and tells the cell to produce some type of cellular activity.
Peripheral proteins
occur on one side of the membrane only-typically cytoplasmic side of membrane; ones on outside of membrane=recognition sites
normally attached to integral proteins
Fxn: enzyme catalysts to affect intracellular events (second messenger system)
Second Messenger System
Classes of intracellular signals acting at or situated within the plasma membrane and translating electrical or chemical messages from the environment into cellular responses
Second messenger system is most important part of the peripheral membrane proteins because they produce cellular activity inside the cell (make things happen from messages from outside cell to inside)
Glycocalyx Fxns
CHO are linked to proteins and lipids on outer surface of cell membrane
- serve in cell to cell recognition processes; participate in immune rxns
- attachment sites for other cells to ECM
- Some (CHO) are charged negatively; act to repel/attract other charged species
- CHO serve as receptors for binding hormones (insulin)
Nucleus
Contains genes encoded as DNA
control center of cell
Genes fxns
Control production of cellular proteins (structural and enzymatic) that ultimately control cytoplasmic and nuclear activity
Nuclear Membrane
contains pores where inner and outer layers fuse
–pores are guarded to restrict mvmt into/out of nucleoplasm
double bilayer
Nucleoli
accumulation of RNA and ribosomes
–storage site for RNA that is ready to translate into proteins
Chromatin
coiled strands of DNA, bound to proteins
Heterochromatin (inactive) appears more electron dense than euchromatin (active)
- H-I=Hetero not active
- Easily Attracted=E-active
Endoplasmic Reticulum
network of interconnected tubular and flat vesicular structures
membrane composed of normal lipid bilayer with endoplasmic matrix inside
produces proteins and lipids for cellular use and for secretion
Small vesicles of ER break away from ER and transport contents to Golgi App for final processing
Rough ER
ribosomes(RNA & PRO) attached to membrane; often continuous with nuclear membrane
produce new proteins for cell and for secretion
Smooth ER
no ribosomes--much like sacroplasmic reticulum steroid production membrane phospholipid production contains numerous enzymes to detoxify Ca+ storage
Golgi Apparatus Fxns
Final packaging center: process substances formed in ER
Synthesize CHO
Concentration of substances in small vesicles: Golgi Apparatus
vesicles release contents via exocytosis
vesicles fuse with plasmalemma to replenish membrane bilayer
some vesicles remain for intracellular uses
Cis face of Golgi App
closest to ER, accepts ER vesicles here
Trans face of Golgi App
nearest plasmalemma, vesicle for export are created here
mitochondria Fxns
-produce energy through aerobic production of ATP
—energy created is stored in high energy phosphate bonds of ATP
–exist in variable amounts in different cells: muscles=most
Contain their own DNA for self replication
Mitochondrial membrane
consists of double lipid bilayer
-inner membrane contains enzymes for converting molecular energy into ATP
Mitochondrial matrix
cytosol w/in the mitochondrion is filled with enzymes for energy extraction from nutrients
Mitochondrial Cristae
(protrusions of inner membrane)
-create greater surface area for enzymatic activity
Lysosome Fxns
final packaging of lysosomes occurs in Golgi App
responsible for digestion of intracellular and extracellular material
exists in different states of activity (optimal activity ion acidic conditions)
Hydrolytic enzymes-(main fxn is digestion) (PRO) synthesized in the RER
Primary Lysosome
contain digestive enzymes only
can release contents into intercellular space
Phagosome: lysosome
vesicle of material taken into the cell from the environment (will fuse with primary lysosome)
Secondary Lysosome
Fusion of phagosome & lysosome
enzymatic digestion takes place–digested material released from the cell via exocytosis
Residual body
remaining indigestible material, usually removed through exocytosis
Cytoskeleton
fibrillar cell proteins organized into filaments or tubules
provides rigid structural support to cells and allows cells to alter shape, contract, and move
Composed of: microfilaments;intermediate filaments;microtubules
Cytoskeleton
fibrillar cell proteins organized into filaments or tubules
provides rigid structural support to cells and allows cells to alter shape, contract, and move
Composed of: microfilaments;intermediate filaments;microtubules
Cytoskeleton Architecture
Actin—same action that they have in the muscular contraction, providing structure and ability to move
Microtubules—acts like a highway
Intermediate filament—architectural structure function, connection to extracellular space
Microfilaments-thin filaments
slender protein strands–5-7 nm thick
Actin is main protein of microfilaments
**Anchor cytoskeleton to membrane proteins–structural support
**Alter viscosity of cytoplasm-more filaments=greater viscosity
**Interact w/myosin to produce change in cell shape or mvmt of cell (contraction)
Intermediate Filaments
7-11nm diameter
different cell types have varied types/amounts of these filaments
FXN: provide strength and stability for cell shape
stabilize organelle positions
stabilize cell position with respect to surrounding cells-via attachment to cell membrane
Common Intermediate Filaments
Keratins: found in skin
Vimentin: mesenchymal cells (CT)
Desmin: muscle cells (smooth, skeletal, cardiac)
Glial filaments: glial cells of CNS (astrocytes)
Neurofilaments: neurons
Microtubules FXN & Characteristics
Maintain cell shape
Participate in intracellular transport of organelles and vesicles providing pathways through the cytoplasm
Make up cilia and flagella
form mitotic spindle for aligning chromosomes during mitosis
composed of alpha and beta subunits of the proteins tubulin
Cilia
move fluid over stationary cell
Flagella
provide cell motility
Thick filaments-myosin
occur as bundles of myosin protein subunits
b/w 12-15 nm in diameter
prevalent in muscle cells–but present in most cell types
interact with actin to produce cellular contraction
Plasticity of Organelles
Amount of organelles and characteristics vary depending on needs of the cell/tissue
Skeletal muscle: plasticity
specialized w/abundant amount of myosin and vast # of mitochondria
Neurons: plasticity
large amounts of RER and microtubules for production and transport of neurotransmitters
Cytoskeleton: plasticity
proportion of components varies among cell types and also with fxn of cell
SER: plasticity
modified in liver cells for detoxification and in skeletal muscle for Ca+ storage
