2- Cells and Tissues Flashcards
Functional characteristics of a cell
cell metabolism and energy use
synthesis of molecules
communication
reproduction and inheritance of DNA
Nucleus
S: nuclear envelope; bilayer membrane
F: control centre
DNA inside nucleus carries code for structural and functional characteristics of the cell
Ribosomes
S: 2 subunits; large + small, free + membrane bound
F: site of protien synthesis, nucleolus, nucleus, cytoplasm
Endoplasmic reticulum
S: flattened; interconnecting sacs and tubules, rough ER (ribosomes), smooth ER (no ribosomes)
F: Rough ER: Synthesis and modification of proteins
Smooth ER: Site of lipid, steroid and carbohydrate synthesis, detox harmful substances, breakdown glycogen -> glucose
Golgi Apparatus
S: Flattened membranous sacs with cisternase, secretory vesicles
F: Modify, package and distribute proteins and lipids
Lysosomes
S: Membrane bound vesicles at golgi apparatus, contains enzymes
F: digest molecules no longer needed by cell
Mitochondria
S: outer;intermediate;inner, matrix, shape continously changes, own genetic material to reproduce
F: produce and supply ATP
Centrioles
S; wall composed of microtubules, two centrioles = 1 centrosome
F: cell division
Cilia
S: motile cellular extensions project from outer surface of cells
F: Movement of substances across surface of cells
Flagella
F: motility
Microvilli
S: extension of plasma membrane, non-motile
F: Increase cell surface area
Cytoplasm
Cellular fluid material outside nucleus
contains organelles and cytosol
Cytosol
Fluid portion of cytoplasm
Consists of ions, proteins
Inclusions: clumps of chemicals made within the cell
contains cytoskeleton
cytoskeleton
supports cell + its organelles
responsible for changes to shape and movement of organelles
contains: microtubules, microfilaments, intermediate filaments
structure of plasma membrane
S:
- Lipid bilayer (Phospholipids bilayers and cholesterol): Provides flexibility to the cell - Carbohydrates (4-8%)
- Proteins (45-50%)
- Glycocalyx (outer surface of cell membrane): establishes a extracelluar micro-environment functions in metabolism.
○ Glycoproteins (Carbohydrates + proteins)
○ Glycolipids (Carbohydrates + lipids)
Carbohydrates
Role of plasma membrane
- Encloses and supports cellar contents
- Controls what goes in and out of the cell
- Role in inter-cellular communication
Histology
Study of tissues
Primary tissues + characteristics
1- Epithelial; covers
2- connective; support
3- Muscle; movement
4- Nervous; control
Characteristics of epithelial tissue
- Distinct cell surfaces; free, lateral and basal
- Avascular but innervates - Ability to regenerate
- Covers and protects
○ Covering and lining epithelium
○ Glandular epithelium
Cell layers
simple, stratified, pseudostratified
describe simple cell layer
single layer of cells
describe stratified cell layer
more than one cell layer
different shapes from lowest to high layers
describe pseudostratified cell layer
one layer
not all reach free surface
cell shapes
squamous
cuboidal
columnar
transitional
Simple Squamous: structure, function and location
1- Single layer, flattened cells, sparse cytoplasm
2- diffusion, filtration, some secretion
3- Alveoli of lungs, kidney, pericardium + peritoneum
Simple columnar: structure, function and location
1- Single layer, column shaped, round+oval nuclei
2- Absorption in intestines, secretion, movement of particles out of bronchioles
3- Kidney tubules, surface of ovaries, glands + ducts
Simple cuboidal: structure, function and location
1- Single layer, cube shaped, some micorvilli/cilia
2- Apsorption, secretion, movement
3- Intestine, stomach, fallopian tubes, lungs
Transitional: structure, function and location
1- Resembles: stratified squamous, stratified cuboidal
2- Accomodate changes in fluid volume
3- Urinary bladder, ureter, upper part of urethra
Stratified squamous: structure, function and location
1- Basal cells; cuboidal/columnar, progressively flatter towards surface, several layers, 2 types (keratinzed+non-keratinzed)
2- Protect against abrasion and loss of water, barrier against infection
3- Keratinzed: skin - sole of feet, palm of hands
Non-keratinized: mouth, oseophagus, cornea
Stratifed cuboidal: structure, function and location
1- Several layers, cubed shaped cells, rare tissues
2- absorption, secretion, protection
3- ducts of sweat glands + salivary glands, developing ovum
Stratifed columnar: structure, function and location
1- Several layers, column shaped cells
2- Secretion, protection
3- Ducts of mammary glands, larynx, part of male urethra
Pseufostratifed columnar: structure, function and location
1- Single layer, column shaped; differing heights, nuclei randomly places, cells ciliated
2- secretion, synthesise mucus, movement
3- pharynx, trachea, lining nasal cavity
Main characteristics of connective tissue
- Most abundant
- Connects and binds together, supports, strengthen, protect, provide energy
- found in all organs; amount varies
What are the cells of connective tissue
?
1- Adipose cells - energy source and cushioning
2- Fibroblasts - secrete fibres and ground substance
3- Mast cells - immunity
4- White blood cells (leucocytes) - repair injury + fight off infection
5- Macrophages - phagcytose foreign molecules
Composition of connective tissue
1- Cells: produce ecm
2- ground substance: fills spaces between cells of connective tissue + where fibres are suspended
3- fibres: collagen, elastic, reticular
Classes of connective tissue
1- CT proper
2- Cartiage
3- Bone
4- Blood
Types of CT proper
1a- Loose areolar 1b - Loose adipose 1c- Loose reticular 2a- dense regular 2b - Dense irregular 2c - Dense elastic
Loose: areolar
F: Loose, support & bind other tissues
L: widely distributed, epithelia of skin
Loose: Adipose
F: nutrient storing, shock absorption + protection, insulation
L: fat beneath the skin, surrounding kidneys - kidneys - breasts
Loose: Reticular
F: Forms framework to support free blood cells
L: lymph nodes, spleen, bone marrow
Dense: Regular
F: attachment
L: tendons (muscles -> bones), most ligaments (bones -> bones)
Dense: Irregular
F: Strength and stretching
L: skin dermis, fibrous coverings surrounding; bones, cartilage, muscles and nerves
Dense: Elastic
F: high recoil and strength
L: walls of arteries, ligaments between spinal vertebrae
CT: Cartilage
- Made of cartilage cells within rigid matric - Avascular, not innervated
F- Protection, flexibility, rigidity, capable to withstanding pressure
Types of cartilage
1- Hyaline: Most abundant; rib cage, trachea, articulating surfaces of bones & nose
2- Fibrocartilage: Intervertebral discs and pubic symphysis
3- Elastic: Ear and epiglottis
CT: Bone
- Supports & protects body structures
- Composed of cells and matrix
- Osteocytes (bone cells) reside in lacunae
Types of CT bone
1- Spongy: Found at ends of long bones, sternum, vertebrae and pelvis
2- Compact: Found in shaft of long bone, makes up outer portion of all bones
CT: Blood
- Atypical; does not provide support or connect anything - Mostly red blood cells, white blood cells and platelets (clotting)
- Transport; nutrients, wastes and respiratory gases
Characteristics of muscle tissue
- Highly cellular
- Well vascularised
- Responsible for body movement
Types of muscle tissue
1- Skeletal - Muscles attached to the bones of the skeleton, hence the name
- Muscle cells are called muscle fibres
- Striated muscle
- Mostly under voluntary control but involuntary movements can occur with skeletal muscle e.g. Twitching
2- Cardiac
- Only found in the walls of the heart, hence the name, where it is responsible for pumping blood around the body
- Striated muscle with intercalated disks
- Under involuntary control
3- Smooth
- Found mainly in the walls of hollow organs e.g. stomach, bladder, uterus, blood vessels.
- No striations and single nucleus per muscle cell
- Under involuntary control
Characteristics of nervous tissue
- Nervous system: brain, spinal cord, nerves
- Main component of nervous system
○ Neurons (nerve cells) - Cell body - Dendrites: input of information
- Axon: conduct and transmit information
- Supporting cells (neuroglia)
