Integrating Cells Into Tissues , organs and systems

Question 1

What. Is the definition of an organ?

Answer 1

• two or more tissues that are combined to create a structural unit.

Question 2

What are the three cells that remain separated from each Their?

Answer 2

1) ova
2) spermatozoa
3) blood corcupsles

Question 3

How are cell types actually formed?

Answer 3

During early embryo development.

• three layers of an embryo are formed.
• outer layer ( ectoderm)
• middle layer ( mesoderm)
• inner layer ( endoderm)

Question 4

What part of the. Embryo are epithelial cells formed from?

Answer 4

ALL parts - ectoderm, ( epidermis) mesoderm( inner linings of body cavities) endoderm ( inner and outer linings of GI tract).

Question 5

What part of the embryo are nerve cells derived from?

Answer 5

• ectoderm

Question 6

What part of the embryo are muscle and connective tissue formed from?

Answer 6

• mesoderm.

Question 7

How do cells join together?

Answer 7

During embryogenesis.

• cells of the same type congregate together and produce cell surface proteins which anchor cells together.
• cells are woven by ic/ECF proteins to create tissue
• the presence of ecm includes connective tissue which connects to muscle cells
• these muscle cells then connect to nerve cells which then connect to blood vessels.

Question 8

Name two fibres that are present in collagen

Answer 8

• collagen
  2) elastin

3) recticular fibres

Question 9

Name 3 cells that are found in connective tissue

Answer 9

1) fibroblasts
2) mesenchyma( stem cell) which interconverts between different cell types
3) adipocytes

Question 10

Name 3 functions of connective tissue

Answer 10

1) protection
2) insulating
3) separation of tissue ( eg tendons)

Question 11

What is the main ground substance in connective tissue ?

Answer 11

Aminoglycans such as. Hyaluroic acid.

Question 12

What is the main role of epithelial tissues ?

Answer 12

Lines all cavities and free surfaces.

Question 13

How Arne epithelial cells held together ?

Answer 13

Cell to cell adhesions

Question 14

Name 4 lateral surface adhesion junctions

Answer 14

1) tight junctions ( top )
2) adhesion belt
3) desmosome
4) gap junctions

Question 15

What is the role of tight junctions ?

Answer 15

Prevents the movement of larger substances and ions through the outer layer

Question 16

What is the role of adhesion belt?

Answer 16

• joins actin bundle in one cell to one similar in another cell.
• only found in epithelial and endothelial cells
• found in pairs
• additional transport barrier

Question 17

What is the role of desmosomes ?

Answer 17

• found in the middle
• provides mechanical strength
• prevents tissue disintegration .

Question 18

What is the role of gap junctions?

Answer 18

• closest to basal surface
  2) found mainly in cardiac and smooth muscle cells so they can quickly communicate changes in electrolyte balance / energy changes.
  3) allows small molecules to pass through eg ions , sugars , amino acids

Question 19

What is the mucosalmembrane ?

Answer 19

• lines all moist hollow organs
• continuous with the skin at various body openings
• secrete mucus ( mucins , lysosomes , immunoglobins , anti septic enzymes)
• prevents pathogens entering body
• prevents dehydration

Question 20

Where is the mucosal membrane mainly found ?

Answer 20

• respiratory tract
• urinary tract
• GI tract

Question 21

What are the 5 layers of mucosa in the GI tract?

Answer 21

1) muscles lines the lumen
2) muscularis mucosa which is thin smooth muscle layer that supports the mucosa

3 submucosa which is connective tissue that contains veins and capillaries

4) muscularis externa : smooth muscle layer : inner is circular and outer is longitudinal
5) serosa : connective tissue which contains collagen , elastin , smaller arteries and veins .

Question 22

What is the function of mucosa in the GI tract specifically?

Answer 22

1) absorb substances from the lumen through specialisations such as microvilli, folds of the mucosa
2) prevent pathogen entry through peristaltic actions , the lamina propia which contains lymphatic tissue
3) move contents and expel waste - muscularis externa performs peristalsis

Question 23

In the kidneys , what type of epithelial cells surround the walls of the bowman capsule ?

Answer 23

Simple squamous epithelial

Question 24

In the kidneys , what type of epithelial cells surround the ducts ?

Answer 24

Simple cuboidal epithelial

Question 25

Is there a muscle layer in the kidneys ?

Answer 25

no , it first appears in the bladder and ureter

Question 26

What type of epithelium is found in the bladder ?

Answer 26

Transitional epithelium

Question 27

What is the role of mucus in specific to the bladder ?

Answer 27

Protects the bladder from damage by acidic urine

Question 28

What is the role of tight junctions in the bladder ?

Answer 28

They were well packed to prevent the leakage of urine to inner cells

Question 29

What is one difference in terms of epithelial structure between the bladder and urethra?

Answer 29

1) in the urethra the epithelium changes from transitional to Stratified squamous.

Question 30

What is the urinary tract summary ?

Answer 30

1) prevent entry of pathogens
2) absorption of nutrients in the kidney
3) removal of waste products