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19 Cards in this Set

  • Front
  • Back

What are the 4 basic categories of mammalian tissue types? And give an example of a specialised tissue which does not fit into these easily.

-Epithelial, Connective, Muscle and Nervous.


-Blood (if any-Connective)

Describe Epithelial tissue, state its function and what its supported by.

- Closely packed cells with little or no intercellular material and non-vascular.


-Cover internal and external surfaces of the body, line the body cavities and ducts and form secretory portions of most glands.


-Usually supported by a basement membrane (connective tissue) which seperates it from the underlying connective tissue.e.g. skin, lining of lungs, gut, salivary glands etc.

State and describe the 6 types of Epithelium

-Layers: Simple (single layer), Pseudostratified (single layer that looks multilayered), Stratified (multiple layers).


-Shape: Squamous (flat cells), Cuboidal (square cells), Columnar (tall cells).

Give examples/describe/state function of:


1. Simple squamous


2. Simple Cuboidal and


3. Simple Columnar


4.Pseudostratified Columnar


5. Stratified Squamous and


6. Stratified Cuboidal/Columnar.

1. Alveoli/Glomerulus (kidney)


2.Kidney tubules/ Ducts


3.Stomach Lining


4.Lining of large Gland Ducts and Organs e.g. Upper Airways Male Urethra


5. Several layers, deepest cuboidal surface squamous. Good protection e.g. Outer skin (Keratinised) Mouth, Oesophagus, Vagina (Non-Keratinised).


6. Stratified Cuboidal/Columnar Protection and Secretion. e.g. Lining of larger gland ducts anal canal, Pharynx (the membrane-lined cavity behind the nose and mouth, connecting them to the oesaphagus.

How are these specialised and why are they specialised? :


- Bronchial epithelium


- Intestinal epithelia

- Cilia to remove and beat inhaled material


- Many finger-like projections called microvilli in order to increase the surface area for absorption.

Describe Connective Tissue , where it occurs and state its function.

Occurs throughout the body and is characterised by cells which are widely seperated by large amounts of extracellular material. Used for support, storage (adipose tissue) and also bone marrow.

State the two types of Connective Tissue and describe them, give their function with examples.

- Loose (areolar) connective tissue, which has low density collagen, reticular and elastic fibres e.g. underlying epithlia.


- Dense regular connective tissue, which has closely packed collagen fibres for strength e.g. tendon.

State the two general types of Nervous Tissue, their functions, description and examples of both.

- Neurons: electrically active cells carrying impulses. Their general structure varies greatly.


-Neuroglia: Surround and support neurons but do not carry impluses. Instead provide insulation for neurons e.g. Schwann Cells (PNS) and Atrocytes (CNS).

Describe the Neuron structore and state all the functions of the different parts.

- Dendrites which receive information
- Axons which conduct the information (may be up to 1 metre and may branch - (collaterals)
- Bouton which contain axon terminals involved in transmission of information to the next cell.
- Myelin Sheath which ...

- Dendrites which receive information


- Axons which conduct the information (may be up to 1 metre and may branch - (collaterals)


- Bouton which contain axon terminals involved in transmission of information to the next cell.


- Myelin Sheath which consist of Schwann cells to provide insulation.


State the 3 types of muscle tissue, their description and their function.

- Skeletal which connects the bones to the skin. Cells are long, striated and multinucleated.


- Cardiac which is the heart muscle. Cells are striated but with some branching.


- Smooth which is in the walls of hollow organs. Non-striated spindle shaped cells.

Describe red blood cells and their function.

-RBC- about 99% (roughly 5x106/ml).


-Biconcave disc to increase surface area and assist diffusion of oxygen and carbon dioxide.


-Non-nucleated with few organelles


-Highly flexible plasma membranes to permit passage through small (roughly 3mm) capillaries.

Describe white blood cells and their function.

- Less than 1% of total blood cells


- Principally involved in defence a function performed by moving out of the blood into the tissue (diapedesis)

What are the 5 types of WBC based on and name them all.

Based on granule content, shape of nucleas and dye affinity.


Granulocytes (contain granules):


-Neutrophills


-Eosinophills


-Basophills


Agranulocytes (do not contain granules):


-Monocytes


-Lymphocytes


Describe the Cell Cycle.

-Interphase:


G1 - cellular contents are duplicated


S phase - Dna/Chromosome replication/


synthesis


G2 - Metabolic changes assemble the cytoplasmic materials necessary for mitosis and cytokinesis + double checks all material and repairs.


-Mitosis:


Prophase - nuclear membrane breaks down, centrosomes organise the production of microtubules that form the spindle fibres that constitute the mitotic spindle. The chromosomes condense into compact structures; sister chromatids held together by the centromere.


Metaphase - The chromosomes align themselves along the metaphase plate of the spindle apparatus


Anaphase - The centromeres divide, and the sister chromatids of each chromosome are pulled apart, and move to the opposite ends of the cell, pulled by spindle fibres to give you daughter chromosomes


Telophase - The nuclear membrane reforms around the chromosomes grouped at either pole of the cell, the chromosomes uncoil and become diffuse, and the spindle fibres disappear.


Cytokinesis:


The final cellular division to form two new cells.


They may have prolonged queiscent periods - G0 phase after G1.


What are CDKs, how are they activated and what determines CDK levels?

The activity of proteins involved in the cell cycle are regulated by cyclin dependent kinases (CDK's) which are a family of enzymes which can phosphorylate specific amino acids in the proteins and activate them. CDK's are themselves activated by binding proteins known as cyclins. Rates of cyclin synthesis and degradation determine cyclin levels and therefore also CDK levels.

State which CDK and cyclin are required at each stage and state how they work.

G1 - CDK2 is required to be activated by cyclin E and then phosphorylates and activates proteins involved in DNA replication. The process is stopped by the degradation of cyclin E.


S phase - mitosis is triggered by the binding of cyclin B to CDK1 which leads to the phosphorylation and activation of proteins involved in mitosis. This process is stopped by the degradation of cyclin B.


Why will cells cultured from young tissue proliferate for longer than cells isolated from an aged source?

Because after each round of cell replication the telomere shortens. Cells can only go through the cell cycle a number of times.

Name the 3 categories in which cells are grouped based on their ability to proliferate and replace and give examples.

- Differentiated cells which cannot proliferate e.g. cardiac muscle.


- Differentiated cells which can proliferate but do so only when needed in response to an injury e.g. hepatocytes in the liver.


- Relatively undifferentiated cells which can proliferate and then differentiate into the cells required (stem cells).

What do stem cells do? e.g. haemopoetic stem cells

They can divide to produce daughter cells that can either remain as stem cells or differentiate into cells that are needed to maintain the tissue. this permits the stem cell population to be maintained and also lost differentiated cells can be replaced.


e.g. Haemopoetic stem cells in the bone marrow maintain the supply of red and white blood cells.