How do cells do what they do? Flashcards
What is the Cell?
Structural & functional unit of all living things.
What are the functional characteristics of cells?
- Cell metabolism & energy use.
- Synthesis of molecules.
- Communication.
- Reproduction & inheritance.
What is the function of the Plasma Membrane-Cell Membrane?
- Encloses & supports cellular contents.
- Controls what goes into and out of the cell.
- Role in inter-cellular (cell-cell) communication.
What is the structure of the Plasma Membrane-Cell Membrane?
-Lipid bilayer (phospholipid bilayer & cholesterol) make up 45-50%. →Provide flexibility to cell. -Carbohydrates (4-8%) -Proteins (45-50%) -Glycocalyx (outer surface of cell membrane) →Glycoproteins (Carbs + Proteins) →Glycolipids (Carbs + Lipids) →Carbohydrates
What is the Cytoplasm?
- Cellular fluid material outside nucleus but within boundaries of plasma membrane.
- Contains organelles + cytosol
What is the Cytosol?
-Fluid portion of cytoplasm (ions + proteins in water).
→Cytoplasmic inclusions- Aggregates of chemicals.
What is the Cytoskeleton?
-Supports cell & its organelles. →Responsible for changes to shape of cell & movement of its organelles. -Microtubules -Microfilaments -Intermediate filaments
What is the function of the Nucleus?
- Control centre of cell.
- DNA in nucleus carries code for structural & functional characteristics of cell.
What is the structure of the Nucleus?
- Nuclear envelope- A bilayer membrane surrounding nucleus. Porous.
- Nucleoplasm.
- Nucleolus- Primarily produces ribosomes.
What is the function of Ribosomes?
-Site of protein synthesis.
→Nucleolus, nucleus & cytoplasm.
What is the structure of Ribosomes?
- Composed of two subunits: large & small.
- Free ribosomes & membrane bound ribosomes.
What is the function of Rough & Smooth Endoplasmic Reticulum?
-Rough ER
→Synthesis & modifications of proteins.
-Smooth ER
→Site of lipid, steroid & carbs synthesis.
→Detoxification of harmful substances.
→Breakdown of glycogen to glucose.
What is the structure of the Endoplasmic Reticulum?
- Flattened, interconnecting sacs & tubules.
- Rough endoplasmic reticulum- with ribosomes.
- Smooth endoplasmic reticulum-without ribosomes.
What is the function of Golgi Apparatus?
Modifies, packages & distributes proteins & lipids that are made in rough endoplasmic reticulum.
What is the structure of Golgi Apparatus?
- Flattened membranous sacs, with cisternae.
- Secretory vesicles.
What is the function of Lysosomes?
- Cells demolition crew.
- Digestions of molecules that are no longer needed by the cell.
What is the structure of Lysosomes?
- Membrane-bound vesicles that form at Golgi apparatus.
- Contains enzymes within them.
What is the function of the Mitochondria?
-Powerplants of a cell.
-ATP production & supply.
→Currency unit for energy
What is the structure of the Mitochondria?
- Outer membrane
- Intermembrane space
- Inner membrane
- Matrix
- Change shape continuously
-Has its own genetic material→reproduce itself.
What is the function of Centrioles?
Cell division
What is the structure of Centrioles?
- Barrel-shaped organelle orientated at right angles to each other.
- Wall of centrioles composed of microtubules.
- Two centrioles can be found in centrosome (cells centre).
What is the function of Cilia?
Movement of substances across the surface of cells.
What is the structure of Cilia?
Whip-like, motile cellular extensions which project from outer surfaces of certain cells.
What is the function of Flagella?
Motility
What is the structure of Flagella?
- Longer than cilia.
- Found on sperm cells only.
- Move the actual cell itself.
What is the function of Microvilli?
Increases cells surface area.
What is the structure of Microvilli?
- Extensions of plasma membrane.
- Non-motile.
What is Histology & its aims?
- The study of tissue.
- Aims to understand micro-anatomy of cells, tissues & organs.
What is Haematoxylin & Eosin (H&E)
- The most common type of stain.
- H stains nuclei purple and other structures are stained pink by E.
What are the Primary Tissues & what do they do?
- Epithelial – covers
- Connective – support
- Muscle – movement
- Nervous – control
What is Epithelial Tissue, what does it do and what does it form?
- Made up of epithelial cells packed together.
- Covers and protects (inside and outside the body)
- Forms boundaries between environments e.g. in epidermis of skin, the epithelial tissue covers and protects the body as well as acting as a boundary between internal and external environments
What are the types of epithelial tissue?
- Covering- covers body
- Lining- lines cavities e.g. cavities of respiratory and digestive systems
- Glandular- forms lining inside glands e.g. sweat or salivary glands)
What are the distinct cell surfaces in epithelial tissue?
- Free surface (not attached to any other cells)
- Lateral surface (side- usually attached to another epithelial cell)
- Basal surfaces (thin, supporting sheet made of proteins secreted by epithelial cells above it) – this attached epithelial cells to underlying tissue (is a filter for epithelium and supports and guides cell migration when tissue is damaged)
Is Epithelial Tissue Avascular & Innervated?
- Epithelial tissue is AVASCULAR (no direct supply of blood vessels) – gets blood from underlying tissue layer (diffuses through basal membrane)
- Is INERVATED- has nerve supply
- Has the ability to regenerate (divide and produce new cells)
What is Epithelial Tissue classified on?
- Classified on number cells and the shape of cells.
- Some have cell surface modifications- cilia (movement) and microvilli (absorption).
What are the cell types of Epithelial Tissue?
- SIMPLE: single layer of cells.
- STRATIFIED: more than one cell layers often w/ different shapes from lowest
(basement membrane) to top (usually cube flattened). - PSEUDOSTRATIFIED: one layer that looks like more layers.
What are the cell shapes of Epithelial Tissue?
- SQUAMOUS: thin, flat cells from side view.
- CUBODIAL: cube shaped (appear square) w/ large, round, nucleus.
- COLUMNAR: tall w/ ovoid nucleus towards base.
- TRANSITIONAL: change shape from columnar to cuboidal (found only in BLADDER and URETERS – allows for expansion).
What is Simple Squamous Epithelium?
- Single layer, flattened cells w/ sparse cytoplasm.
- For diffusion, filtration and some secretion.
- Found in alveoli of lungs (quick gas diffusion from blood to lungs), kidney glomeruli (filter blood), serous membranes of pleura, pericardium and peritoneum (secrete fluids).
What is Simple Cuboidal Epithelium?
- Single layer, cubed shaped.
- Some have microvilli or cilia.
- Absorption, secretion and movement.
- Found in kidney tubules (secretion and absorption) and terminal bronchioles (cilia move mucus).
What is Simple Columnar Epithelium?
- Single layer, tall/column w/ ovoid nuclei.
- Some have cilia.
- Absorption, secretion and movement.
- Found intestines (absorb nutrients), stomach (secrete mucus), fallopian tubes (movement ovum in reproductive tract), lungs (move debris/unwanted particles out of bronchioles).
What is Traditional Epithelium?
-Accommodate changes in fluid volume of organs.
-One state= unstretched and tall, other state= stretched and flattened.
-Found in urinary bladder, ureter and upper part of urethra.
oWhen empty= stratified cuboidal.
oWhen full= stratified squamous.
What is Stratified Squamous Epithelium?
- Basal cells are cuboidal or columnar and become progressively flatter (squamous) towards surface – several layers of cell.
- Can be keratinized (tough, waterproof) or non-keratinized (not as tough).
- Protects against abrasion and H2O loss (in dry environment).
- Keratinized in sole of feet, palm of hands, skin.
- Non-keratinized in mouth (movement of food), oesophagus, vagina (sex), anus (movement of faeces) places w/ lots of friction.
- Many layers= if one layer comes off, still various layers underneath to protect tissue.
What is Stratified Cuboidal Epithelium?
- Several layers cubed-shaped cells, nucleus in middle (round).
- Rare tissue.
- Absorption (may have villi), secretion (cube=plump can make secretions, flat cannot), protection (many layers).
- Found in sweat gland ducts, ducts salivary glands, developing ovum.
What is Stratified Columnar Epithelium?
- Several layers, column shaped.
- Rare tissue.
- Secretion (tall) and protection.
- Ducts of mammary glands, parts male urethra, larynx.
What is Pseudo-Stratified Columnar Epithelium?
- One layer, column shaped cells (different heights)- try look for nuclei.
- Cells are ciliated.
- Secretion and movement.
- Found in pharynx & trachea (secrete mucus to trap debris – cilia move it out), male’s sperm carrying ducts (secretions for sperm maturation, cilia move out of reproductive system).
What is Connective Tissue?
Most abundant & widely distributed primary tissue in the body.
What is the function of Connective Tissue?
Connects & binds together, supports, strengthens, protects, insulates, compartmentalise, transports & provides energy.
Where is Connective Tissue located?
All organs & parts of the body but amount varies.
What is the composition of Connective Tissue?
- Cells-produce extracellular matrix.
- Ground substance-ECM
- Fibres-ECM
Where are the cells of Connective Tissue & what do the do?
- Adipose Cells- Energy & cushioning.
- Fibroblasts- Secrete fibres & ground substance.
- Mast Cells- Immunity.
- White Blood Cells- Repair injury & fight off infection.
- Macrophages- Phagocytose foreign molecules.
What are ground substance of Connective Tissue?
Fills spaces between cells of connective tissue and the space where fibres are suspended.
What are the fibres of Connective Tissue?
- Collagen fibres
- Elastic fibres
- Reticular fibres
What are the classes of Connective Tissue?
- Connective tissue proper.
- Divided into dense & loose forms.
- Dense= Regular, irregular & elastic.
- Loose= Areolar, adipose & reticular.
In the loose class of Connective Tissue what is the function & location of Areolar?
Function
-Loose packing, support & binding of the tissues.
Location
-Widely distributed throughout the body.
In the loose class of Connective Tissue what is the function & location of Adipose?
Function -Nutrient storing ability. -Shock absorption & protections -Insulation. Location -Fat beneath the skin.
In the loose class of Connective Tissue what is the function & location of Reticular?
Function
-Forms framework to support free blood cells.
Location
-Spleen, bone marrow & lymph nodes.
In the dense class of Connective Tissue what is the function & location of Regular?
Function
-Attachment.
Location
-Tendons & most ligaments.
In the dense class of Connective Tissue what is the function & location of Irregular?
Function
-Provides strength & stretching.
Location
-Skins dermis, fibrous coverings surrounding bones, cartilages, muscles & nerves.
In the dense class of Connective Tissue what is the function & location of Elastic?
Function
-Has high recoil & strength.
Location
-Walls of arteries & ligaments between spinal vertebrae.
What is Cartilage?
- Made of cartilage cells within a rigid matrix.
- Avascular & not innervated.
What is the function of Cartilage?
Provides protection, flexibility, rigidity & capable of withstanding pressure.
What are the Cartilage types & their locations?
- Hyaline C- Most abundant & found in rib cage, trachea, articulating surfaces of bone & nose.
- Fibrocartilage- Found intervertebral discs & pubic symphysis.
- Elastic cartilage- Found in ear & epiglottis.
What does bone do & what is it composed of?
- Supports & protects body structures.
- Composed of cells & matrix.
- Osteocytes (bone cells) reside in lacunae.
What are the types of bone?
- Spongy: Found at ends of long bone, sternum, vertebrae & pelvis.
- Compact: Found in shaft of long bone & makes up outer portions of all bones.
What is blood as a tissue?
- A typical connective tissue in that it doesn’t provide support or connect anything.
- Mostly red blood cells & scattered white blood cells & platelets.
- Transports nutrients, wastes & respiratory gases around the body.
What is Muscular Tissue?
-Highly cellular, well vascularised & responsible for most body movement.
Types: Skeletal, cardiac & smooth.
What is Skeletal Muscle Tissue?
- Muscles attached to the bones of skeleton.
- Muscle cells are called muscle fibres.
- Straited muscle.
- Mostly voluntary control but involuntary movements can occur eg: twitching.
What is Cardiac Muscle Tissue?
- Only found in the walls of the heart, where it is responsible for pumping blood around the body.
- Straited muscle with intercalated disks.
- Involuntary control.
What is Smooth Muscle Tissue?
- Mainly in walls of hollow organs (stomach, bladder ect).
- No striations & single nucleus per muscle cell.
- Involuntary control.
What is Nervous Tissue?
- Brain, spinal cord and nerves.
- Nervous tissue is the main component of the nervous system.
- Neurons (nerve cells).
- Supporting cells (neuroglia).
What are Neurons comprised of?
Cell body- Soma
Dendrites-Input of information
Axon-Conductions/transmitting information
