Chapter 3- Cells & Tissues Flashcards
What are the 3 main regions of the Generalised Cell
Nucleus- usually located near the centre of the cell
Cytoplasm- surrounds the nucleus in it’s semifluid
Plasma Membrane- encloses the cytoplasm & forms the outer cell boundary
Cells are made up of what elements
- Carbon
- Oxygen
- Hydrogen
- Nitrogen
Where is DNA/ Genetic Material held in a cell
Nucleus
Why is DNA important?
It is necessary for cell reproduction, it contains instructions for building the whole body
A cell that has lost or ejected it’s nucleus is programmed only to die
What are the 3 regions of the Nucleus
- Nuclear envelope
- Nucleoli
- Chromatin
What is the Nuclear Envelope
It is the double membrane barrier that bounds the nucleus
What is between the 2 membranes of the nuclear envelope
A fluid filled moat
Define: Nucleoli
One or more small, dark staining, essentially round bodies contained in the nucleus
Nucleoli are sites where cell structures called RIBOSOMES are assembled
Define: Chromatin
A loose network of bumpy threads scattered throughout the nucleus, formed when DNA is combined with protein
Define: Plasma Membrane
is a fragile, transparent barrier that contains the cell contents and separates them from the surrounding environment
The Plasma Membrane:
Structure
Double phospholipid layer:
Hydrophilic heads
Hydrophobic tails
Contains: proteins, cholesterol, and glycoproteins
Function of the Plasma Membrane
Communication between cells
Forms cell junctions for tissues
Provides cell identification
Regulates transport of molecules
What are the 3 types of Membrane Junctions
- Tight junctions
- Desmosomes
- Gap junctions
What are Tight Junctions
- Impermeable junctions that encircle cells and
* Binds cells together into leakproof sheets
What are Desmosomes
Anchoring junctions that prevent cells from being pulled apart
Gap Junctions: function
They allow communication between cells
Define: Cytoplasm
Is the cellular material outside the nucleus and inside the plasma membrane
-It is the site of most cellular activities
What are the 3 main elements of Cytoplasm
- Cytosol
- Organelles
- Inclusions
Define: Cytosol
Is the semitransparent fluid that suspends the other elements
Define: Organelles
Are the metabolic machinery of the cell
Each type of organelle is specialised to carry out a specific function for the cell as a whole
Define: Inclusions
Are the chemical substances- Most inclusions are stored nutrients or cell products
such as lipid droplets (common in fat cells), pigments (melanin in skin & hair cells) etc
What are the 2 major Gland Types
Endocrine gland
Exocrine gland
Define: Vesicular Transport
Involves the help from ATP, moves substances into or out of cells without their actually crossing the plasma membrane
What are the 2 types of Vesicular Transport
- Exocytosis- moves substances out of the cell
2. Endocytosis- moves substances into the cells
Define: Tissues
A groups of cells that are similar in structure and function
4 Primary Tissue Types
- Epithelial tissue (epithelium)
- Connective tissue
- Muscle tissue
- Nervous tissue
Define: Epithelial tissue
Is the covering, lining and glandular tissue of the body. (skin)
Glandular tissue forms various glands in the body
Function of Epithelial tissue
Protection, absorption, secretion, filtration, excretion and sensory reception
Name some characteristics of Epithelial tissue
- Cells fit closely together and often form sheets
- The apical surface is the free surface (top)
- Lower surface rests on a basement membrane
Epithelial tissue: 2 cell layer names (indicating the number of cell layers)
Simple- one layer of cells
Stratified- more than one layer of cells
Classifying Epithelium involves 2 sets of names. What does the first and second name indicate
First Name- indicates relative number of cell layers it has
Second Name- describes the shape of its cells
What are the shapes of Epithelial tissue
Squamous- flattened
Cuboidal- cube shaped
Columnar- column like
Define: Pseudo
False
Name all Epithelial tissue type
Simple squamous Stratified squamous
Simple cuboidal Stratified cuboidal
Simple columnar Stratified columnar
Pseudo Stratified Transitional
Explain: Simple squamous
Simple layer of flat cells
Location:
- lines body cavities
- lines lungs & capillaries
Function:
- diffusion, filtration or secretion
Explain: Simple cuboidal
Single layer of cube like cells
Locations
- common glands & their ducts
- forms walls of kidney tubules
- covers the ovaries
Functions
- secretion & absorption, reproductive cells
Explain: Pseudo Stratified columnar
Single layer, but some cells are shorter than others
-Looks like a double layer of cells but all cells rest on the basement membrane
Location:
- respiratory tract
Function:
- absorption & secretion
Define: Connective tissue
Connects the body parts
It is the most abundant and widely distributed of the tissue types
What is the Function of Connective tissue
Primarily involved in protecting, supporting and binding together other body tissues
What are the 2 Characteristics of Connective tissue
- Variations in Blood Supply- most connective tissue is well vascularised (they have a good blood supply)
- Extracellular Matrix- non living, ground substance plus fibres produced and secreted by the cells
What are the 5 types of Connective Tissue
- Bone
- Cartilage
- Dense Connective tissue
- Loose Connective tissue
- Blood
What are osteocytes
Bone cells
Connective Tissue:
What is Bone composed of
Osteocytes sitting in cavities called lacunae (pits)
What is the major cell type for Cartilage
Chondrocytes (cartilage cells)
Define: Chondrocytes
Cartilage cells
What cartilage type is the most widespread
Hyaline Cartilage
Define: Hyaline Cartilage
- Has abundant collagen fibres
- Forms the supporting structures of the larynx, attaches the ribs to the breastbone and covers the end of bones, where they form joints
Other than hyaline cartilage, what are the other 2 types of Cartilage
Fibrocartilage
Elastic cartilage
Define: Fibrocatilage
Highly compressible, forms the cushion like disks between the vertebrae
Define: Elastic Cartilage
Is found in structures with elasticity
eg. supports the external ear
What is the substance found between the disks of the vertebrae
Fibrocartilage
Define: Dense Connective tissue
Forms strong, rope like structure. such as tendons & ligaments
Function of Tendons
Attaches skeletal muscles to bones
Function of Ligaments
Connects bones to bones at joints
Ligaments are more stretchy and contain more elastic fibres than tendons
Define: Loose Connective tissue
Are softer and have more cells and fewer fibres than any other connective tissue type except blodd
Why is blood considered a Connective Tissue
(Vascular Tissue)
Because it consists of blood cells, surrounded by a non living, fluid matrix called blood plasma
Define: Vascular Tissue
Blood
Define: Muscle Tissue
They’re highly specialise to contract to produce movement
How many types of Muscle Tissue are there
3
Name the 3 types of Muscle Tissue
Skeletal- attached to bone
Cardiac- forms the heart
Smooth- in the walls of hollow organs
Define: Nervous Tissue
Is composed of irritable cells called neurons, which are highly specialised to receive and transmit nerve impulses
Name the 2 ways Tissue Repair occurs
Regeneration- the injured tissue is replaced by the same type of cells
Fibrosis- the wound is repaired by dense fibrous connective tissue, which is the formation of scar tissue
Define: Cell
Cells are the structural units of all living things
Where can you find Simple Squamous epithelium?
Lungs
Where can you find Simple Cuboidal epithelium?
Kidney tubules
Where can you find Simple Columnar epithelium?
small intestines
Where can you find PseudoStratified Columnar epithelium?
Trachea
Where can you find Stratified Squamous epithelium?
Oesophagus
Where can you find Transitional epithelium?
Lining of the Bladder
