Histology

Question 1

Structure of Artery and arterioles

Answer 1

Lumen
Endothelium
Intima - loose connective fibrous tissue
Internal elastic lamina
Media - high amounts of elastic tissue near heart
External elastic lamina
Adventitia

Question 2

Capillary Structure

Answer 2

Single layer of endothelial cells on basement membrane
Some sections have holes - fenestrated epithelium
Pericytes wrap around sections of capillary to regulate size by constriction

Question 3

Vein structure (in comparison to arteries)

Answer 3

Have no external elastic lamina
Thinner media but larger lumen
Contain valves

Question 4

Lymphatic structures

Answer 4

Thin walled (similar to capillaries and veins)
Have valves
Contain eosinophilic lymph

Question 5

Erythrocytes

Answer 5

No nucleus
Form 43% of blood
Formed from the bone marrow (liver in foetus)
120 days lifespan
Biconcave discs held together by spectrin cytoskeleton
Destroyed in liver and spleen
7.5 microns in diameter

Question 6

Leukocytes (what are they lol)

Answer 6

White blood cells (1% of blood)

Question 7

Granulocytes

Answer 7

Not many in blood
Primary granules - Lysosomes (Myeloperoxidase and acid hydroxases)
Secondary granules - for inflammatory response
Tertiary granules - Gelatinases and adhesion molecules

Question 8

Neutrophils

Answer 8

primary phagocytes and are 40-75% of leukocytes
Multilobed nucleus
Granular cytoplasm (containing myeloperoxidase)
Increase in number with bacterial infection or inflammation
Release chemotaxins and cytokines which are important in the inflammatory response
One cell produces many cells by becoming more mature as they divide

Question 9

Eosinophils

Answer 9

Roughly 5% of leukocytes
Numbers increase in parasitic infections
Large red cytoplasmic granules with crystalline inclusions
bi/tri lobed nucleus
Antagonistic in action to basophils and mast cells as they neutralize histamine

Question 10

Basophils

Answer 10

make up 0.5% of leukocytes
Bi-lobed nucleus
Blue staining cytoplasmic granules
Contain and release histamine
Involved in inflammatory reactions and act to prevent coagulation and agglutination

Question 11

Lymphocytes

Answer 11

20-50% of leukocytes
Agranular and both look the same
B cells - plasma cells secrete immunoglobulins and mature in bone marrow
T helper – help B cells and activate macrophages (CD4)
T Cytotoxic – Kill previously marked target cells (CD8)
T Suppressor – suppress TH cells and so suppress immune response
T cells mature in thymus

Question 12

Monocytes

Answer 12

make up 1-5% of leukocytes
Reniform nucleus (kidney bean shaped)
Multipotent cells - differentiate to macrophages, kupffer cells etc
major phagocytic and defensive role

Question 13

Platelets

Answer 13

fragments of cells formed from megakaryocytes
have no nucleus but contain smaller organelles
contain vesicles containing coagulation factors
Alpha granules - Platelet derived growth factor (PDGF) and Von Willebrand factor
Gamma granules - electron-dense and contain small molecules (serotonin), critical for platelet activation and vasoconstriction
Peroxisomes – contain catalase for the elimination of oxygen radicals
Lysosomes

Question 14

Pericardium structure

Answer 14

Layer of squamous mesothelial cells resting on thin layer fibrous connective tissue
Visceral – layer on outer layer of the heart
Parietal – layer of cells on inner cell of fibrous sac containing the heart

Question 15

Epicardium

Answer 15

The underlying adipose loose connective tissue, vessels and nerves
Between pericardium and myocardium

Question 16

Myocyte structure

Answer 16

Striated cardiac muscle
central nuclei
branching with intercalaced discs which connect actin
discs contain gap and adhering junctions, desmosomes
Atrial myocytes smaller than ventricle myocytes

Question 17

Purkinje Fivres

Answer 17

Subendocardial
Large vacuolated muscle cells
Found immediately below the ventricle

Question 18

Endocardium

Answer 18

thin layer of fibrous connective tissue them

endothelial (simple squamous) tissue

Question 19

Respiratory epithelium

Answer 19

Lines tubular portion of the respiratory system
Pseudostratified columnar
Contain ciliated epithelial cells and goblet cells

Question 20

Opening of nostril

Answer 20

Stratified keratinizing squamous epithelium

Question 21

Further down nostril

Answer 21

Stratified non-keratinizing squamous epithelium

Question 22

Unreachable nasal cavity

Answer 22

Respiratory epithelium

Question 23

Connective tissue behind nose epithelium

Answer 23

Richly vascular lamina propina

Contain seromucous glands

Question 24

Roof of basal cavity (olfactory epithelium)

Answer 24

Pseudostratified ciliated columnar epithelium of olfactory receptor cells
Stereocilia (non motile) and no goblet cells
Have supporting sustentacular cells and basal cells
Serous glands of Bowman
Number of nerves

Question 25

Nasopharynx

Answer 25

Lined with respiratory epithelium

Question 26

The larynx

Answer 26

Hyaline cartilage holds the larynx open against negative pressure during inspiration
Lined with respiratory epithelium with layers beneath
Loose fibro collagenous stroma with seromucinous glands
Then Perichondrium – dense connective tissue
Then hyaline cartilage

Question 27

The vocal cords

Answer 27

Stratified squamous epithelium overlying loose irregular fibrous tissue
Blood vessels but almost no lymphatics
Vocal ligament - Dense fibrous connective tissue
Vocalis muscle

Question 28

Trachea

Answer 28

Respiratory epithelium
Seromucinous glands in submucosa
Trachealis muscle posteriorly between rings
C-shaped cartilaginous rings 
Hyaline cartilage
Perichondrium on both sides

Question 29

Bronchi

Answer 29

Smooth muscle
Partial cartilaginous rings
Respiratory epithelium
Some basal neuroendocrine cells 
Seromucinous glands and goblet cells

Question 30

Bronchioles

Answer 30

Smooth muscle
Partial cartilaginous rings
Respiratory epithelium
Some basal neuroendocrine cells 
Seromucinous glands and goblet cells

Question 31

Alveoli

Answer 31

Type 1 pneumocytes - Squamous cells with a flattened nucleus and few organelles
Type 2 pneumocytes - Rounded to columnar cells with a round nucleus and rich in mitochondria and ER and produce surfactant to lower surface tension