Lecture 2- Tissues

Question 1

What’s Epithelial Tissue?

Answer 1

Epithelial Tissue-lines internal passageways, membranes (covers exposed surfaces) and forms glands

Question 2

What are the 2 different types of cells?

Answer 2

A simple cell has one layer of cells, in this cell it’s easy for stuff to pass through so they’re located in areas used for secretion and absorption. They can’t offer protection so there located in protected areas i.e. the heart chambers and lining passageways.
A stratified cell has multiple layers of cells, good for protection- loss top layers without damaging deeper layers.

Question 3

What are the different shapes of cell?

Answer 3

• Squamous-flat/thin/squashed cell with the nucleus inside, smooth cell so good for covering
• Cuboidal- cube shaped, often line tubes (especially line gland)
• Columnar- column shaped, a lot taller than wide
• Transitional- can change shape between being squamous and cuboidal therefore it can be stretched without being damaged.

Question 4

What are the features of an Epithelial cell?

Answer 4

• They have an exposed surface on the top of the cell called an Apex and the bottom surface is called the basal surface (this stops stretching and creates a border)
• At the bottom of the basal surface is the basal membrane which joins to a connective tissue
• Microvilli on the Apex surface and mitochondria near the basal surface because this is where the openings are so energy is needed for transportation
• Cell junctions attach cells together, allowing communication between them
• Cells are Avascular so have no blood vessels meaning nutrients and waste exchange is done by diffusion
• if the cells get damaged they get replaced by cell division

Question 5

Describe a simple squamous epithelial cell

Answer 5

Simple Squamous Epithelial- found in lining of blood vessels and alveoli (found where diffusion occurs). Its functions are it reduces friction, controls vessel permeability, performs absorption and secretion and they have a smooth lining so move easily.

Question 6

Describe a stratified squamous epithelial cell

Answer 6

Stratified Squamous Epithelial- found at the skins surface and lines the mouth and throat. Its functions are it provides protection against abrasion, pathogens and chemical attacks.

Question 7

Describe a simple cuboidal epithelial cell

Answer 7

Simple Cuboidal Epithelial- they’re found in areas where secretion and absorption occur, offer limited protection and form the lining of a tube e.g. in the kidney

Question 8

Describe a stratified cuboidal epithelial cell

Answer 8

Stratified Cuboidal Epithelial- lines sweat and larger mammary glands but are rare, same functions as above

Question 9

Describe a transitional epithelial cell

Answer 9

Transitional Epithelial- found in urinary bladder, these cells need to change to hold differing amounts of urine. When the bladder is empty the cells are cuboidal but when the bladder is full the shape is squamous. Its functions are that it permits expansion and recoil after stretching.

Question 10

Describe a simple columnar epithelial cell

Answer 10

Simple Columnar Epithelial- found in lining of stomach and intestines often in areas of secretion and absorption- taller cells provide more protection.

Question 11

Describe a pseudostratified ciliated columnar epithelial cell

Answer 11

Pseudostratified Ciliated Columnar Epithelia- means it looks like its multiple layers but there not. One layer but different heights of cells. It contains cells of different shapes and functions. Found on cells that line the bronchi, trachea (lines places that produces mucus), it can move mucus with cilia.

Question 12

Describe a stratified columnar epithelial cell

Answer 12

Stratified Columnar Epithelia- Has several layers, either 2 or multiple layers, with a gap in the middle, allows more protection but is much rarer.

Question 13

What shapes are glands?

Answer 13

Gland shapes are tubular, coiled, branched and alveolar

Question 14

What’s a glandular epithelia

Answer 14

Glandular Epithelia- these are a collection of epithelial gland cells that are specifically used in secretion

Question 15

What are the 2 main types of gland cells

Answer 15

• Endocrine Glands- they produce endocrine secretion known as hormones, these get released into the bloodstream. Hormones regulate or control activities in tissues or organs and examples include the pituitary and thyroid gland.
• Exocrine Glands- they produce exocrine secretion which get released by going through tubular ducts onto the skin or epithelial surfaces. Examples include enzymes and perspiration. Can classify exocrine glands in 3 ways, by the structure of the glands, or by how those glands secrete their products, and by what those products are.

Question 16

What are the 3 main methods that gland cells secrete their product?

Answer 16

• Merocrine method= Cells produce protein in the saliva, called secretary vesicle and these are discharged at the surface.
• Apocrine method= In the mammary gland, proteins are produced which gather at the top of the cell and the cell will break down and then re-grow.
• Holocrine= Happens in stratified cells, cells division replaces lost cells, then cells produce secretion and increase in size, then the whole cell bursts, releasing contents

Question 17

What’s a connective tissue?

Answer 17

Connective tissue is a collection of a diverse group of supporting tissues which contain cells and fibres and they’re functions are mechanical support, protection and padding. They have 3 components: specialised cells, extracellular protein fibres and have a fluid called a ground substance.

Question 18

What are the main functions of connective tissues?

Answer 18

• Establishing a structural framework for the body
• Transporting fluids and dissolved materials
• . Protecting delicate organs.
• Supporting, surrounding, and interconnecting other types of tissue.
• Storing energy, especially in the form of triglycerides.
• Defending the body from invading microorganisms.

Question 19

What’s fibroblasts and adipocytes

Answer 19

Fibroblasts are fibres releasing cells. Adipocyte= a fat cell.

Question 20

What are the 3 fibres

Answer 20

Collagen= strong, flexible and thick fibres with no branches, they’re the most common
Reticular smaller and thinner with lots of branches, giving an interwoven 3D structure that’s tough but flexible. They can resist forces from many directions because they’ve formed a network
Elastic stretchy, look like collagen but less strong, are in cells that need to expand and contract so once the force causing them to stretch has been removed, they revert to their original shape.

Question 21

What’s ground substance?

Answer 21

The fibres sit in a goo called Ground Substance, could be a fluid like blood or a gel (for cartilage) or mineral (for a bone) and it fills the gaps between cells.

Question 22

What’s the components in the blood?

Answer 22

• Red blood cells transport oxygen and gasses
• White blood cells fight off pathogens
• Platelets- stop blood clots, they exist in Plasma which is a fluid containing proteins, salts and antibodies so they move quickly around the body.

Question 23

What’s a loose connective tissue

Answer 23

Loose connective tissues- they fill spaces between organs, absorb shocks and stabilise specialised cells.

Question 24

What’s Adipose tissue

Answer 24

Adipose Tissues-large portion of the cell is fat, it stores fat and energy, the cells are squishy so good for padding, its useful for cushioning shocks/falls and provides insulation so reduces heat loss. This tissue is common in skin at the sides, in the breasts and buttocks.
Has a fluid ground substance

Question 25

What’s Reticular tissue

Answer 25

Reticular tissues- narrow fibres proving supportive 3D structures, keeps kidney and liver cells in the right place.
Has a fluid ground substance

Question 26

What’s dense connective tissue

Answer 26

Dense Connective Tissue- used in tendons and ligaments, have a lot of strength when you pull on the tendon/ligament.

Question 27

What are the 2 types of dense connective tissue

Answer 27

Regular tissue- the fibres are arranged in parallel, packed tightly together and align with the forces applied to the tissue. Ligaments and Tendons ae regular. Cells only get pulled in one direction.
• Irregular connective tissues create a meshwork with no pattern to it, the tissue supports areas that have force applied to them from many directions, so cells get pulled in many directions.

Question 28

What’s elastic tissue

Answer 28

Elastic Tissue- has elastic fibres rather than collagen fibres so is much more stretchy

Question 29

What’s hyaline cartilage

Answer 29

Hyaline Cartilage has smooth surface with a bit of bounciness, it’s tough but flexible due to the closely packed collagen fibres but not as many as its mainly ground substance which is jelly like and there’s gaps in the jelly called lacunae- this is where the cells sit. These exist in the nasal cartilage and the cartilage passage along the respiratory tract.

Question 30

What’s elastic cartilage

Answer 30

Elastic Cartilage- has a jelly like ground substance too however this one has elastic fibres instead of collagen fibres meaning it’s much more flexible and less strong. Found in the ear cavity and down the windpipe.

Question 31

What’s fibrocartilage

Answer 31

Fibrocartilage- has even more collagen fibres (all densely woven together) and less of the jelly like ground substance meaning its very tough and durable.

Question 32

Describe mucous membrane

Answer 32

Mucous membrane- they line respiratory lining and they line passageways that open to the exterior. The epithelial cells must be moist so that secretion and absorption can occur and to reduce friction, their lubricated by mucous.

Question 33

Describe serous membrane

Answer 33

Serous = Some membranes line ventral body cavities. These membranes are very thin but are firmly attached to the body wall or organ they cover.

Question 34

Describe cutaneous membrane

Answer 34

Cutaneous membrane – is the skin surface that covers your body, its thick, quite waterproof and usually dry.

Question 35

Describe synovial membrane

Answer 35

Synovial membrane- adjacent bones interact at joints and the synovial membrane lines joint cavities and produces fluid (called synovial fluid) within the joint. This stops bones from rubbing together as joints are used for movement, if the joint isn’t used for long periods of time it causes the cartilage and synovial membrane to deteriorate.

Question 36

What’s the 3 layers of Fasciae

Answer 36

Fasciae- these are connective tissue layers that support and surround organs, there’s 3 layers of Fasciae.

1. Superficial Fasciae= layer of tissue separating the skin from underlying tissue and organs. It lets the skin and underlying structures move more freely and provides insulation and padding.
2. Deep Fasciae= made up of dense regular connective tissue, the fibres run in the same direction but each layer changes orientation so the tissue can resist forces from many directions.
3. Subserous Fasciae= It lies between the deep fasciae and the serous membrane so it separates the 2 meaning movement doesn’t distort the body cavity lining.

Question 37

Describe skeletal muscle tissue

Answer 37

Skeletal muscle tissue- adjacent lined up tissue, they’re very long cells, only one under voluntary control, are very large with multiple nuclei and the muscle contracts when the nerve tells it to.

Question 38

Describe cardiac muscle tissue

Answer 38

Cardiac muscle tissue- specifically found in the heart, interlaced for communication, contracts for the beating of the heart, can slow down or speed up but is involuntary, has smaller, thinner and branched cells. Its controlled by pacemaker cells which transmit electrical signals around the heart and it has limited ability to repair itself.

Question 39

Describe smooth muscle tissue

Answer 39

Smooth muscle tissue- found in gut wall, walls of blood vessels and around hollow organs. The cells are smaller and smooth, the nerve system can control some contraction of the tissue, but it isn’t under voluntary control. It regulates respiratory and blood vessels diameters.

Question 40

Describe neural tissue

Answer 40

Neural tissue- this specialises in moving electrical pulses to different regions in the body.

Question 41

Describe a Neuron

Answer 41

Neurones vary in shapes and sizes with lots of branches so can make lots of connections.
Axon is a long nerve that can communicate with other cells that are further away in the body.
Supporting cells are called neuroglia.
Dendrites- contact other neurons