Chapter 3- Cells & Tissues Flashcards by Miss J

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

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Cells are made up of what elements

Carbon
Oxygen
Hydrogen
Nitrogen

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Where is DNA/ Genetic Material held in a cell

Nucleus

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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

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What are the 3 regions of the Nucleus

Nuclear envelope
Nucleoli
Chromatin

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What is the Nuclear Envelope

It is the double membrane barrier that bounds the nucleus

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What is between the 2 membranes of the nuclear envelope

A fluid filled moat

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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

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Define: Chromatin

A loose network of bumpy threads scattered throughout the nucleus, formed when DNA is combined with protein

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Define: Plasma Membrane

is a fragile, transparent barrier that contains the cell contents and separates them from the surrounding environment

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The Plasma Membrane:

Structure

Double phospholipid layer:
Hydrophilic heads
Hydrophobic tails

Contains: proteins, cholesterol, and glycoproteins

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Function of the Plasma Membrane

Communication between cells
Forms cell junctions for tissues
Provides cell identification
Regulates transport of molecules

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What are the 3 types of Membrane Junctions

Tight junctions
Desmosomes
Gap junctions

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What are Tight Junctions

Impermeable junctions that encircle cells and

* Binds cells together into leakproof sheets

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What are Desmosomes

Anchoring junctions that prevent cells from being pulled apart

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Gap Junctions: function

They allow communication between cells

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Define: Cytoplasm

Is the cellular material outside the nucleus and inside the plasma membrane

-It is the site of most cellular activities

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What are the 3 main elements of Cytoplasm

Cytosol
Organelles
Inclusions

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Define: Cytosol

Is the semitransparent fluid that suspends the other elements

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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

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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

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What are the 2 major Gland Types

Endocrine gland

Exocrine gland

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Define: Vesicular Transport

Involves the help from ATP, moves substances into or out of cells without their actually crossing the plasma membrane

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What are the 2 types of Vesicular Transport

Exocytosis- moves substances out of the cell

2. Endocytosis- moves substances into the cells

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Define: Tissues

A groups of cells that are similar in structure and function

4 Primary Tissue Types

1. Epithelial tissue (epithelium) 2. Connective tissue 3. Muscle tissue 3. 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

1. Variations in Blood Supply- most connective tissue is well vascularised (they have a good blood supply) 2. Extracellular Matrix- non living, ground substance plus fibres produced and secreted by the cells

What are the 5 types of Connective Tissue

1. Bone 2. Cartilage 3. Dense Connective tissue 4. Loose Connective tissue 5. 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

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