Histology Flashcards
Explain the name simple squamous epithelium
simple= 1 layer squamous = squashed
Where would you find simple squamous epithelium? (3)
Lining blood vessels, air sacs of the lungs, kidney
What is the basement membrane called in simple squamous epithelia?
Basal lamina
Function of simple squamous epithelium
Allows exchange of nutrients, waste & gases
What organelle is visible in simple squamous epithelium?
Nucleus
Which type of epithelium is present in kidney tubules and glands?
Simple cuboidal epithelium
Explain the name simple cuboidal
simple = 1 layer cuboidal = square shaped
Where is the nucleus located in simple cuboidal epithelium?
Central
Function of simple cuboidal epithelium
secretes, excretes & reabsorbs water and small molecules
Explain the name pseudostratified columnar epithelium
pseudostratified = 1 layer but appears there are many due to the many nuclei columnar = tall cells
Where is pseudostratified columnar epithelium located?
Trachea, oesophagus (Upper respiratory tract)
What cytoplasmic projections do pseudostratified columnar epithelium have?
Cilia
What do cilia in pseudostratified columnar epithelium contain>
Bundles of microtubules
Function of cilia in pseudostratified columnar epithelium (2)
- Increase SA
- beat synchronously to help move mucus along the respiratory tract
Type of cells in pseudostratified columnar epithelium
Goblet cells
Function of goblet cells
Secrete mucus to catch bacteria
What type of epithelia are goblet cells more common in?
Glandular epithelia
Function of pseudostratified columnar epithelium (2)
Secretion, absorption
What type of epithelium does the surface of skin of the human scalp have?
Stratified squamous epithelium
What are the 2 skin appendages in the skin?
Hair follicles, sweat glands
3 layers of the skin
Epidermis
Dermis
Hypodermis
Which layer of the epidermis contains dead keratinocytes?
Stratum corneum
White section of skin histological slide
Adipose tissue
What pigment does the stratum basale contain
Melanin
What type of collagen fibres does the skin contain?
Dense irregular fibres
What glands are attached to the hair follicles?
Sebaceous glands
Describe what dense irregular connective tissue is
Collagen fibres in all directions
Function of keratinocytes
Secrete keratin- provides waterproof layer
What is desquamation?
Cells dying and rising to the top layer (stratum corneum) to shed
Which layer of the epidermis do cells divide in?
Stratum basal
Function of melanocytes
Produce melanin - pigment
Function of sebaceous glands
Produce sebum
Function of sweat glands
Produce sweat
2 Types of sweat glands
Eccrine & apocrine
5 layers of epidermis (inc. layer in thick skin - state this) from TOP TO BOTTOM
Stratum corneum Stratum lucidum (thick skin) Stratum granulosum Stratum spinosum Stratum basal
Describe the cells in stratum granulosum
cells contain granules which are full of lipid-rich secreion; water sealent
Describe the cells in the stratum spinosum
cells have many desmosomes which allows them to anchor to one another. contain keratin
Which layer of the skin contains elastin and collagen fibres?
Dermis
name 2 regions of the dermis
Superficial region = papillary dermis
Deeper region = reticular dermis
Which region of the dermis contains loose CT
Superficial
Which region of the dermis contains dense CT
deeper
Which region of the dermis extends into the epidermis? and what are the projections called?
Papillary dermis.
dermal papillae
Which region of the dermis contains fibroblasts, macrophages and adipocytes?
Reticular dermis (deeper region)
Which layer of the dermis do the hair follicles originate?
Dermis
What type of glands are sweat glands?
Exocrine
What type of epithelium lines the sweat glands?
Simple cuboidal
What type of epithelium lines the ducts of the sweat glands?
Stratified columnar
What type of secretion occurs in exocrine glands
Holocrine
Describe the cells in the sebaceous glands
Rounded vacoules filled with lipids
What organ has both exocrine and endocrine function?
Pancreas
What is the exocrine section of the pancreas composed of?
closely packed acini cells
What epithelia surround the pancreatic ducts?
Columnar
What are the sections of the exocrine pancreas called?
Lobules
Where are the ducts located in exocrine pancreas (2)?
within the lobules - intralobular ducts
outside of the lobules - extralobular ducts
What are extralobular ducts in pancreas surrounded by?
CT
What are intralobular ducts in pancreas surrounded by?
Acini
Where do the islets of langerhans secrete hormones?
Directly into the blood
How are the hormones secreted in the exocrine pancreas?
Via zymogen granules
what is the name of one unit in the lobule of exocrine pancreas
Acini
What is an acini?
A group of cells which all secrete into zymogen granules. nuclei are arranged on the periphery of the acini
What cells make up the Islets of Langerhans?
(neuroendocrine cells) Alpha, beta, delta, PP
What do beta cells secrete?
Insulin
What do alpha cells secrete?
Glucagon
What do delta cells secrete?
Somatostatin
What enzymes are secreted by exocrine pancreas?
Trypsin & chymotysin
What are the islets of langerhans supported by?
Reticular fibres
What is aroud each islet?
Capsule
Where is the duodenum
Small intestine
Name the layers of the duodenum
Mucosa
Submucosa
Muscularis
Adventitia
What is contained within the mucosa?
Villi
Function of villi
To increase SA for absorption
What type of cells are contained within the villi of the duodenum>
Goblet cells = secrete mucus Enterocytes = absorption
What is the outer layer of the villi called?
Brush border
Where is the lamina propria?
Mucosa
What type of cells are contained within the lamina propria?
Lymphocytes
Macrophages
Plasma cells
What colour do the goblet cells look like on the histological slide of the duodenum?
White
What CT makes up the lamina propria?
Loose connective tissue
Where are the crypts in the duodenum?
Base of villi
What do the crypts secrete?
Pancreatic juice
What type of cells are at the base of the crypts? (2)
Paneth cells and endocrine cells
Function of paneth cells
Secretes lysosomes; defensive function
What to the endocrine cells of the duodenum secrete?
Secretin, somatostatin, enteroglucagon
Where does cell proliferation take place in the duodenum?
Crytps
What type of glands are in the submucosa of the duodenum?
Brunner’s glands
Function of brunner’s glands
secrete mucus to protect duodenal lumen
What is the submucosal plexus and its function?
Neural tissue which regulates contractions and glandular secretions
Name the layers of muscularis duodenum and their location
Circular (inner) and longitudinal (outer)
C comes before L in alphabet
What are the layers of the mucularis covered by?
Serosa
Shape of circular muscularis
Compact spiral
Shape of longitudinal muscularis
Elongated helix
What type of glands are within the liver?
Exocrine
What type of cells surround the central vein?
Hepatocytes, reticular endothelial cells, macrophages
What type of cells are between the hepatocytes?
Red blood cells
Function of hepatocytes
Secrete bile
What are the basic units in liver tissue?
Lobules
Which vein in the liver is surrouned by CT and which is not?
Central vein - no CT
Hepatic portal vein - CT
How to differentiate between the central vein and portal vein?
Portal vein has cells around the periphery
What is the bile duct surrounded by in the liver?
Epithelia - cholangiocytes
Explain the pathway of bile flow from the hepatocytes
Bile canaliculi , bile duct, hepatic duct
Pathway of blood flow in liver
Sinusoids, central vein, hepatic portal vein, inferior vena cava
Which 2 vessels supply the liver?
Hepatic artery - blood
Hepatic vein - nutrients from GI tract
What type CT does the liver posses?
dense CT
What makes up the liver lobule?
Central vein which is surrouned by 6 portal canals in a hexagonal arrangement.
name for 3D arrangement of hepatocytes
Hepatic laminae
What is inbetween hepatic laminae
Hepatic sinusoids which are endothelial lined
What are canaliculi in liver?
Grooves between hepatocytes - where bile is secreted
Name 2 sections of the adrenal gland
Cortex & Medulla
What type of tissue is on the outer layer of adrenal gland?
Adipose
What type of gland is the liver and both its regions?
Endocrine
Which section of the adrenal gland is on the outer edge and which is on the inner edge?
Outer - cortex (c comes first in alphabet)
Inner - medulla
What type of cells are contained within the medulla?
Ganglion cells
Where did the medulla derive from?
The neural crest
What hormones do the granular cells of the medulla contain>
Adrenaline & noradrenaline and cholesterol
From outer to inner, name the layers of the cortex of the adrenal gland
Zona Glomerulosa
Zona Facsiculata
Zona Reticularis
What type of hormones does the zona glom. secrete and give examples.
Mineralcorticosterioids- aldosterone
What type of hormones does the zona fascic. secrete and give examples.
glucocorticoids - Cortisol
What hormones does the zona retic. secrete?
Androgens & oestrogens
Where is the thyroid gland locates?
Anterior surface of the trachea
Basic unit of thyroid gland
Lobule
What do the lobules contain
Follicles of hormones
What hormones are made within the lobules and what is the function of them ?
Thyroxine (T4) & Triiodothyronine (T3) - metabolism
Where is calcitonin made in the thyroid gland?
Cells in between follicles = parafollicular cells
Function of calcitonin
Calcium homeostasis
What epithelium does the follicle contain in thyroid gland?
Cuboidal
What is the lumen of the thyroid gland follicle contained with?
Colloid
What structures are inbetween the lobules in the thyroid gland?
Blood vessels and CT
What is colloid?
Inactive T3 & T4 bounded to glycoprotein (thyroglobin)
Is smooth muscle striated?
No
How many nuclei are in each strand in smooth muscle?
1
How is the nucleus positioned in smooth muscle?
centrally
What shape do the nuclei have in smooth muscle?
Fusiform
Function of smooth muscle
Involuntary
Location of smooth muscle
Blood vessels, skin, resp system, digestive system, urinary, reproductive
Is skeletal muscle striated?
Yes
Describe the arrangement of the striations of the straited muscle to the skeleton?
Parallel
Muscle which is voluntary
Skeletal
Describe the arrangement of the fibres in skeletal muscle
Longitudinal
Each fibre in skeletal muscle is multinucleated. True or false?
True
What do the skeletal muscle fibres contain?
Fused myoblasts
What are the fibres in skeletal muscle surrounded by?
Loose CT
What does Loose CT contain?
Collagen and elastin fibres
What is the striation?
Sarcomere = many myofibrils
Muscle which is involuntary and has striations
Cardiac
Where is the only place you’ll find cardiac muscle?
The heart
What is a main characteristic of cardiac muscle?
the striations are interconnected with each other
What connects the sarcomeres in cardiac muscle?
Intercalated discs
What type of cell is contained within cardiac muscle?
Myocytes
What are the white sections in the cardiac muscle slide?
Glycogen
Position of nuclei in cardaic muscle
central
3 types of junctions in cardiac muscle
Anchoring junctions
Desmosomes
Gap junctions
which has a thinner wall, artery or vein?
Vein
which has a larger lumen, artery or vein?
vein
Which has more elastic and collagen prominent layers, artery or vein?
Artery
Describe the intima in the vein
Thin endothelial lining
Which layer of the vein has very little smooth muscle & elastin
Tunica media
Which tissue is contained within the T.Adv of the vein?
Loose CT
Which layer of the vein contains collagen fibres and the vasa vasorum?
Tunica Adventitia
Which have a greater vasa vasorum, artery or vein?
Artery
Describe T.Media of the artery
Smooth muscle & sheets of elastin and collagen
Describe T.Adv of the artery
vasa vasorum, loosely woven collagen & elastin fibres
Another name for white fibrous CT
Dense regular tissue
What makes regular tissue dense?
Linear direction of the fibres
Where will you find dense regular tissue?
Tendons & ligaments
What fibres are contained within dense regular tissue?
Collagen
What type of cells are contained within dense regular tissue and what is their function?
Fibroblasts - secrete collagen
What is the white fibrous tissue mainly made out of?
Extracellular matrix
What specific cells are contained within white fibrous tissue?
Dividing cells
Where are reticular fibres found?
Liver, lymph node, spleen (immune system)
What tissue are reticular fibres classed as?
CT
What fibres are contained within reticular fibres?
Collagen fibres