Histology Flashcards
what colour does H&E stain?
blue and pink
what stain would you use for sugars, cartilage collagen and gycogen?
PAS - magenta
what stain would you use for elastic?
Van Gieson
what stain would you use for mucins?
Alcian Blue
when would you use this stain?
Osmium - heavy metal
stains for lipids.
identified myelinated neurons
what stain has been used here?
Perls’ Prussian Blue
Detects Iron
what type of cell is this, where would you find it, and what is their function?
simple squamous epithelium.
alveoli, lining of heart, blood vessels and lymphatic vessels
allow passage through diffusion, secrete lubricating substance.
what type of cells are these, what is their function and where would you find it?
Simple cuboidal epithelium.
> secrete and absorb
> found in small ducts and kidney tubules.
what are these celss, what is their function and where can they be found?
Simple Columnar Epithelium
> absorb and secretes mucous and enzymes
> .Cilliated: found in bronchi, uterine tubes, uterus (wafting)
> Non cilliated: digestive tract (villi) and bladder
what type of cell is this?
where might it be found?
Pseudostratified Columnar Epithelium.
Cilliated
Respiratory Epithelium
where is stratified epithelium found?
parts of body exposed to frequent friction:
skin, mouth, cervix, oesophagus, vagina
continuously worn down
what types of cells are these?
Stratified Squamous Non-Keratinising Epithelium.
Keratin helps to waterprood epithelium - not needed in wet sights.
Top = oesophagus, Bottom = Vagina
where might you find each of these two cells?
This is Stratified Squamous Keratinising Epithelium.
Keratin = waterproofing.
The left is thin skin = eyelids
The right is thick skin = palm of hands
What are these cells and where would you find these kinds of cells?
Urothelium
(looks stratified, but umbrella cells dont touch basement membrane)
Found in Bladder, urethra, Ureters - allow urinary ograns to expand and stretch.
what is a basement membrane made from?
bonus: what stain would you use?
Collagen IV and Fibronectin
PAS (-magenta)
what junction is this?
what is it used for?
where might you find it?
Gap Junction - communication
>transfer/electrically couple
smooth and cardiac muscle
what type of junction is this and what is its function?
Desmosomes
share mechanical load of cells
what do tight junctinos do.
where could you find them?
Prevent diffusion between cells - establish and conc gradient.
eg Gut: only small molecules can pass
what is collagen secreted by?
Fibroblasts (secrete tropocollagen)
where would you find Type I, II, III, IV and V collagen?
Type 1: skin
Type II: Cartilage
Type III: liver, bone marrow, spleen (reticulin)
Type IV: Basement Membrane
Type V: Placenta
what are the arrows pointing to?
Where are the nucleus?
Collagen - extracellular
Nucleus = that of fibroblasts
how would you stain for reticulin?
silver stain.
where would you find brwon adipose tissue?
across the shoulders of newborns.
important in neonatal thermo-regulation
what are chondroblasts and chondrocytes?
immature and mature cartilage
what is this? where is it found?
hyaline cartliage:
- blue/grey matrix - no visible fibres
- entrapped chondrocytes
Found in synovial joints (knee, septum)
what is this and where is it found?
Elastic Cartilage
- visible elastin fibres and chondrocytes
Found in Epiglottis and Pinna
what type of cartilage is this?
Fibrocartilage
- Visible Collagen in matrix
Found in Intravertebral discs and symphysis pubis
This is Synovium.
Where would you find it?
Lines the inside of joint capsule.
Type A = phagocytes
Type B = rER
Vascular and innervated
what type of muscles are the following?
Is it striated?
Central Nuclei?
Branching?
Skeletal = Striated, edge, non Branching
Cardiac = Straiated, Central, branching
Smooth = non, central, non
from in to out, name the general structure of a blood vessel
which is missing from Arterioles?
veins?
venules?
Intima - Endothelium, BM, ConnTiss
Internal Elastic Lamina - fenetrated elastin
Media - Smooth Muscle, Collagem, Elastim
External Elastic Lamina - less defined elastin
Adventitia - Loos ConnTiss, Nerve, vasa vasorum
arterioles = no external elastic lamina
veins = no external or internal elatic lamina
veunules = no external or internal elastic lamina or media
capilliaries = only intima
what type of blood vessel is this and where would it be found?
elastic artery: much, well defined elastin in media
found in arteries near hearts eg aorta, PA
what is an arteriole defined as?
3 or fewer muscle layer in the media
what is it that regulates the size of capillaries?
pericytes
what is this? how can you tell?
Lymph.
Has valves, no blood, can cdee lymphocytes
what can you see here?
peripheral nerve (left)
arteriole (top right)
venule (bottom right)
most peripheral nerves are myelated (insulated sheath)
what cells produce myelin?
Schwann Cells
what is the red arrow pointing to in this silver-stained slide?
Gap between Schwann cells
= Nodes of Ranvier
In a myelinated axon in PNS how many schwann cells would you expect to see on a single axon?
A single cell myelinates 1.5mm long segments
label the arrows
what is the purpose of myelin?
myelinated axons are larger and transmit impulses faster than unmyelinated ones.
what is the pericadium made from?
squamous medothelial cells
what is the epicardium made from?
layer of fatty connective tissue, may see vessels and nerves
what is the myocardium made from?
specialised cardiac muscle
- striated, centralised, branching, discs!
what are the intercalated discs in the myocardium?
specialised connections between myocytes (connect actin filaments)
contain gap junctions, adhering junctions and desmosomes
where would the largest myocytes be found?
Left ventricle
What are the neuroendocrine granules of the heart and where would you find them?
Atrial Natriuretic peptide in the
myocardium of atrium.
released when cells are excessively stretched
describe the conducting system of the heart
SA node –> AV node –>His –> Purkinje fibres
what is this?
bonus: what stain?
Purkinje Fibres!
PAS
what is lipofuscin?
“aging pigment”
brownish pigment left over from breakdown and absorbytion of damaged blood cells - can be found in hte smooth muscle and cardiac muscle
what is the endocardium made from?
- thin layer of fibrous connective tissue
- single flat layer of endothelial cells on inner most surface (simple squamous)
what layer of the heart covers cardiac valves?
endocardium
what are the three layers of a cardiac valve?
- fibrosa
- spongiosa
- ventricularis
who is she?
platelet:
no nucleus, granules
1-3µm
who is she?
basophil
(blue granules)
who is she?
eosinophil - bilobes nucleus
parasites
phagocytic and neutralise histamine
who is she?
neutrophil
multi lobed
phagocytic
who is she?
monocyte
kidney shaped nucleus
differentiate unto several things
who is she?
lymphocyte - seem all nucleus!
b and T cells
Draw out the stages of haematopoeisi on a whiteboard
what are reticulocytes?
immature red blood cells
outline erythropoeisis
reduce cell size
produce heamoglobin
loss of organelles
basophillia –> eosinophilia
expell nucleus
mediated by erythropoeitin
happens AWA from bony trabeculae
Q1. What proportion of the blood is made up of white blood cells?
1%
plasma = 56%
red cells = 43%
white = 1%
where are these cells formed in adults?
These are erythrocytes. In utero they are formed first in the yolk sac, then in the liver, then in the bone marrow. In adults, haematopoiesis is confined to the marrow of the flat bones and proximal ends of the humeri and femurs. Red cells are destroyed in the liver and spleen.
what is the predominant leukocyte?
neutrophils
Granulocytes (contain visible granules)
40-75% Neutrophils
~ 5% Eosinophils
~ 0.5% Basophils
Agranulocytes (no visible granules)
20-50% Lymphocytes
1-5% Monocytes
Platelets (cell fragments)
Q4. A patient has a Strongyloides stercoralis infestation. This is a parasitic roundworm. Numbers of which cell type increase in patients with worms?
Eosinophils play a role in our defence against parasitic infections and their numbers increase in patients with parasites such as worms.
which leucocyte produce histamine?
basophils
which leukocytes are phagocytic?
Eosinophils, neutrophils and monocytes are phagocytic.
what cells secrete antibodies?
plasma cells
what can monocytes give rise to?
Tissue macrophages - everywhere
Kupffer cells – liver
Osteoclasts – bone
Antigen presenting cells - everywhere
Alveolar macrophages – lung
Q3. Which of these is a feature of a ventricular cardiac myocyte?
Formed from multiple myoblasts
Fusiform cells
Multinucleate
Myofibrils in register
Secrete hormones
Their myofibrils are in register, and so they appear striated.
where are purkinje fibres found?
immediately below endocardium
Q6. How do the myocytes of the sinoatrial node differ from normal cardiac myocytes?
no intercalated discs
Q8. Where in the heart will you find the nodules of Arantius?
aortic valve cusps
The nodules of Arantius are nodules of fibroelastic tissue on the centre of the free edge of each of the valve cusps in the aortic valve and pulmonary valve. They are more prominent in the aortic valve (due to increased pressure in that side of the circulation).
Q11. Which cells in the heart contain Weibel-Palade bodies?
Weibel-Palade bodies are storage granules found within the cytoplasm of endothelial cells (in the heart and elsewhere). They contain von Willebrand factor and other vascular mediators.
Q12. Which of the following lacks lymphatics?
Brain
Cartilage
Heart
Lung
Small intestine
Although it was long thought that the heart and brain did not have lymphatic vessels within them, it is now known this is not the case. Almost all tissues have lymphatics, except cartilage, the eye, bone marrow and perhaps spinal cord.
what type of vessel is this?
This is a muscular artery, such as the radial or splenic artery. The media comprises smooth muscle with very little elastin. Elastic arteries are much larger.
what type of vessel is this?
This is an arteriole – made harder to recognise as you cant see the adjacent venule clearly (there is just a little of its wall in the bottom left corner). It is a small afferent vessel, less than 100 um thick/less than 3 layers in the media.
label the arrows
Q10. How many axons are myelinated by a single Schwann cell?
1
While a single axon will be myelinated by many Schwann cells (with intervening nodes of Ranvier), each Schwann cell myelinates only a single axon. This is in contract to unmyelinated axons, many of which may be supported by a single Schwann cell.
Q12. If the structure shown relates to sensory peripheral nerves, where is it?
dorsal root ganglia
Q7. In the trachea, cilia beat rhythmically to propel mucus towards the larynx. Which two proteins are principally involved in the generation of ciliary movement?
Tubulin and dynein
what do hemidesmosomes do?
Hemidesmosomes bind the basal cell layer to the basement membrane.
Q12. A gland secretes by shedding individual cells. What type of secretion is this?
holocrine
Secretion via loss of entire cells from the gland is holocrine secretion.
Merocrine secretion is release of cell products by exocytosis from apical cell surface.
Apocrine secretion involves pinching off part of the apex of the cell.
Apocrine, merocrine and holocrine are all types of exocrine secretion.
Endocrine secretion is release of products from the cell base into the blood stream.
what are the visable extracellular fibres?
what forms the ground substance?
The visible fibres in extracellular material are collagen, elastin and reticulin. Fibronectin and laminin are invisible fibres. Glycosaminoglycans and proteoglycans form the ground substance.
Q9. Which of the following contains dense regular fibrous connective tissue?
Arterial adventitia
Dermis
Penile erectile tissue
Penile fascia
Tendon
Dense regular connective tissue is characterised by having all of the collagen fibres running in the same orientation. It is found in ligaments and tendons.
The penile fascia comprises dense irregular connective tissue.
The adventitia of arteries comprises loose irregular connective tissue.
The dermis contains dense and loose irregular connective tissue.
Penile erectile tissue comprises numerous blood vessels and dense irregular fibrous CT bounded by a dense irregular fibrous CT fascia.
what type of muscle is this and where would it be found?
This is smooth muscle. It is found in the walls of blood vessels, in the walls of the airways, in the walls of the gut, ureters, vas deferens etc. and forms the muscular layer (myometrium) of the uterus.
What cells make up the mucosa of the stomach?
- columnar epithelium - mucus secreting cells
- parietal in body and fundus
- chief in body and fundus
- g cells in cardium and pylorus
Label each image/where it is found.
- Duodenum: stratified glandular epithelium, Microvilli, brunner’s mucus secreting glands.
- & 3. Jejunum and ileum: simple columnar epithelium, Villous mucosa, Microvilli, Crypts of Lieberkuhn, Enterocytes, pareth cells, goblet cells, absorptive cells, lymphocytes, enteroendoncrine cells
- Ileum = peyer’s patches
Where would the myenteric plexus of Auerbach be found?
Jejunum & ileum: between circular & longitudinal layers of smooth muscle
What are these cells and where could they be found?
Interstitial cells of Cajal
Muscular is proprietary of small intestine
Where in the body could there cells be found?
Colon
Flat, no villi, straight crypts, looks more structured than stomach
What are these cells an example of?
Coeliac disease: crypt hyperplasia & villas atrophy in duodenum
How does the muscularis proprietor of the gut differ from the stomach?
Gut has two layers, stomach has three
Where in the mouth is this least
likely to have originated from?
Posterior third of tongue The image shows stratified squamous non-keratinising epithelium over a loose fibrous connective tissue stroma. This is found throughout the mouth. However, in the posterior third of the tongue, the epithelium overlies a lymphoid infiltrate (part of Waldeyer’s ring) as shown on the right.
Where are the circumvallate
papillae?
Anterior 2/3 tongue
The circumvallate papillae form a V-shaped line between the anterior two-thirds and posterior third of the tongue.
What do filliform papillae do?
Filiform papillae are the most numerous of the papillae on the tongue, but they do not contain taste buds. Instead, they roughen the dorsal surface of the tongue, which possibly aids in mastication.
Which salivary gland is this? How can you tell?
This is a purely serous salivary gland (mucous glands have clear cytoplasm), and so must be parotid.
The submandibular gland is mixed mucous/serous. The sublingual gland, buccal and lingual glands are mostly mucous glands.
This is the oesophagus.what feature confirms its site of origin?
A. Mucinous glands in the submucosa
B. Non-keratinising stratified squamous epithelium
C. Serous glands in the submucosa
D. Squamous lined ducts
E. Sub-epithelial lymphocytes
Oesophageal mucosa is recognised by the presence of a non-keratinising stratified squamous epithelium (but this is found in the mouth as well), lymphocytes in the submucosa, and mucinous glands in the submucosa that have squamous-lined ducts. The ducts are unique to the oesophagus and let us be confident this sample is from the oesophagus.
Note: Although the textbook states that the gland ducts are lined by columnar epithelium, this is wrong – it is squamous (or, at most, in places, cuboidal)
Where does this tissue originate from?
Duodenum
Gastric antrum
Gastric body
Gastric cardia
Gastric fundus
Where does this tissue originate from?
Duodenum
Gastric antrum
Gastric body
Gastric cardia
Gastric fundus
Gastric antrum
Long branching crypts lined by mucus secreting cells.
Lack of parietal cells(rues out body t fundus)
Mucus - more than half thickness in antrum and pylorus (about 50% in cardia)
Dudodensl mucosa would have villous architecture
What do parietal cells secrete?
Intrinsic factor and gastric acid
From where does this fissure originate? What do the glands in its submucosa secrete?
Duodenum: broad, leaf like villi
Submucosal brunner’s glands
Brunner’s glands secrete an alkaline mucus neutral se that helps gastric acid
Where does this tissue originate from? R
Ileum
Note the villas architecture prominent lymphoid aggregates (peyer’s patches) in the submuscosa and mucosa.
These lymphoid aggregates are not present in the jejunum or duodenum.
The appendix and colon do not have a villous architecture.
Which statement about the histology of the colon is true?
A. Auerbach’s plexus lies in the muscularis propria
B. It has a prominent brush border
C. It is lined by a serous epithelium
D.The caecum has a different histology to the ascending colon
E. The muscularis propria has three layers
A.
Two autonomic nerve plexuses innervate the gastrointestinal tract: Meissner’s plexus lies in the submucosa, Auerbach’s plexus lies between the layers of the muscularis propria.
The colon has a double-layered muscularis propria – inner circular, outer longitudinal.
The epithelium comprises a simple columnar layer of mucus-secreting enterocytes.
The histology of the different parts of the colon is the same.
Which statement about this tissue is the?
It does not have a muscularis mucosae
It is normal gastric body
It is supplied by a branch of the coeliac axis
It is the site of vitamin B12 absorption
Stem cells are located at the base of the crypts
This is colonic mucosa, and the epithelial stem cells lie at the base of the crypts of Lieberkhun. You cannot tell which part of the colon it comes from, as the entire colon looks the same.
The colon does have a muscularis mucosa, immediately below the lamina propria.
The colon is supplied by the superior mesenteric artery and the inferior mesenteric artery. Vitamin B12 is absorbed in the terminal ileum.
What are these cells called?
Hepatocytes (usually contain glycogen)
Can see portal tract & central veins
Liver is usually divided into classic lobules. Describe this structure
Classic lobule = are a drained by one central hepatic venule. Roughly hexagonal
What structures can be found in the portal tract?
Bile duct, portal vein, hepatic artery
In the classic lobule, which hepatocytes are most likely to be richly oxygenated.
The hepatocytes towards the edge
These are hepatocytes when the liver has undergone schematic damage. Where is the central venue and portal tracts likely to be locate?
How can we tell that These are heaptocytes?
Polyhedral epithelial cells
bundant mitochondria (granular cytoplasm)
Large spherical central nuclei
Prominent nucleoli
May be binueate
This is part of the intrakepartic biliary tree. Which part is the red star pointing to?
Bile ductule (simple cuboidal)
Describe the epithelium of the parts of the biliary tree from intrahepatic to extrahepatic
What to hepatocytes synthesize?
Bile
What are the three important surfaces of hepatocytes?
Sinusoidal(70 %) = permits exchange of material with blood
Canalicular (15%) = permits excretion of bile
Intercellular (15%)
What is the space between the sinusoidal space in hepatocytes called?
Space of diss
Name two things that can be found in the space of Disse
- reticulin fibres
- Ito cells (liver stem cells - fat storing)
What are sinusoids (form sinusoidal space of hepatocytes)
- Highly specialised, FENESTRATED blood vessels
- No basement membrane
- contain scattered kupffercells
What is this? Where can it be found and what does it do?
Kupffer cell
Found in sinusoid
Phagocytes/defence
help produce bilirubin
What is the function o the gallbladder?
Stores & concentrates bile by absorbing water
Where do these cells originate from?
Gallbladder:
Describe the specialised mucosa of bad the gall bladder
The exocrine function of the pancreas is what % of its function
90%
What is the exocrine function of the pancreas?
To synthesize and secrete enzymes & bicarbonate rich fluid into the duodenum
The epithelial cells of the exocrine pancreas are arranged in what?
Acini
Describe the acinar epithelium of the pancreas
Describe the epithelium of the ducts of the pancreas
Name 5 functions of hepatocyte’s
(i) the creation and storage of energy in the form of glycogen and fats;
(ii) the synthesis and secretion plasma proteins;
(iii) the deamination of amino acids and the production of urea;
(iv) the uptake, synthesis and excretion of bilirubin and bile acids;
(v) The detoxification and inactivation of drugs and toxins by oxidation, methylation or conjugation.
True I false: 80 % of the livers blood supply comes from hepatic artery
False. Mostly from portal vein. Only 30 % of livers blood supply from hepatic artery
What is bile secreted by?
Hepatocyte’S.
What are kuppfer cells derived from?
Monocytes.
They are phagocytes
Found in hepatic sinusoids
What do the arrows cells secrete?
What do the arrows cells secrete?
What type of epithelium is this?
Respiratory epithelial - pseudo stratified columnar
(Goblet cell& cilia labelled)
Which parts of the respiratory system are not lined by respiratory epithelium?
Roof of nasal cavity: olfactory epithelium
Vocal chords: stratified squamous
Bronchioles: cuboidal ciliated
Alveolar: squamous epithelium
What type of epithelium can be found in the nose? (3)
Anterior: keratinising squamous
Posterior: non-keratinising squamous
Roof of nasal cavity: pseudostratified columnar ciliates epithelium(olfactory epithelium)
Where in the body could these be found?
Nose
Respiratory epithelium
Richly vascular Latimina propria containing seromucinous glands
What type of epithelium is this? How can you tell?
Olfactory epithelium
- penetrating nerve fibres
- rich network of serous glands of Bowmann
Where would this be found?
Label this.
What is the gap between the c-shaped cartilaginous rings of The trachea?
What is it made from?
Trachealis
Vertical smooth muscle
What is the difference between segmental bronchi & bronchioles, histologically?
I what are these cells? Where can they be found? What do they do?
Clara cells
- mitochondria, secretory, smooth er, No cilia
-Most numerous in terminal bronchioles
- uncertain purpose (oxidise inhaled toxins? Antiprotease? Surfactant production/elimination? Stem cell? Secrete lipoprotein?)
Where would this be found?
What is the irregular fibrous tissue called?
Vocal chords: -
-Stratified squamous epithelium (not respiratory)
- almost no lymphatic
Fibrous tissue= reinke’s space
What are the layers of the visceral pleura?
L. Irregular internal elastic
2. Interstitial fibrocollagenous layer
3. Irregular external elastic
What is the diameter of an alveoli?
250 micrometers
What do type l preumocytes do?
40% of cell population
90% of surface area
Squamous epithelium
Thin as possible for gas exchange l
Which cells produce surfactant?
Type II pNeumocytes
Which preumocytes are most numerous?
Type 2=60% of cell population, 5-10% of SA
Type 1= 40% of cell population, 90% of SA
Label the cells of the alveoli
What do alveolar macrophages do? Where are they found?
- phagocytes particulates including dust & bacteria
What are the layers of the blood - air barrier?
- Surfactant
- Type 1 pneumocyte
- Fused basement membrane of pneumocyte & capillary
4 . Vascular endothelial cell
Q2. Which of these is lined by respiratory epithelium?
Alveoli
Bronchi
Nares
Roof of nasopharynx
Vocal cords
Bronchi
Respiratory epithelium lines the conducting airways and sinuses. It is therefore present in the bronchi.
The alveoli are lined by pneumocytes.
The nares are lined by stratified squamous keratinising epithelium
The vocal cords are lined by non-keratinising stratified squamous epithelium.
The apex of the nasopharynx is lined by olfactory epithelium.
Q3. What type of tissue holds open the larynx and trachea?
Hyaline cartilage
Which part of the respiratory system is this?
Roof of nasophaninx = olfactory epithelium
Where is reinke’space?s
In the vocal chords
Reinke’s space is occupied by the loose irregular fibrous tissue in the vocal cords
Reinke’s space lies between the vocal epithelium and the vocal ligament. Beneath that is the vocalis muscle.
How thick is the blood-l
How thick is the air-blood barrier?
600 nm
where in the kidney would these cells be found?
what structures are found here?
Cortex - Glomeruli, proximal and distal convoluted tubules
where in the kidney would these cells be found?
what are the two blue arrows pointing to?
medulla
loop of henle (L)
blood vessels (R)
what are the green arrows pointing to?
medullary rays = collection of loops of henle and collecting ducts originating from nephrons that have their renal corpuscles in the outer part of the cortex ∴ nephrons with glomerulus close to the capsule areradially orientated.
where in the kidney is this?
the pelvis
describe the structure of a glomerulus
what it is + 3 cells
the glomerulus is the filtering unit of the kidney
- a tuft of convoluted fenestrated capillaries on a BM
- lined by podocytes
- supported by mesangial cells
- encased in Bowman’s capsule.
this is a glomerulus.
what are the bottom two arrows pointing to?
top - capillary endothelial cell (inside capilleries)
bottom = mesangial cell (between capillaries)
what is the mesangium made from and what are its three functions?
smooth muscle
1. structural support for the capillary and production of extracellular matrix protein
2. contraction of muscle in the glomerulus tightens the capillaries and reduces glomerular filtration rate (tubuloglomerular feedback)
3. phagocytosis of glomerular basement membrane breakdown products.
describe the Glomerulus basement memrane
double thickness (glomerular capillery + podocyte BM) and negatively charged
describe the layers of the Glomerulus BM
lamina lucida interna
double lamina densa
lamina lucida externa
(two BMs back to back)
label this glomerulus
what prevents the movements of large molecules, such as albumin, from entering the urine.
glomerulus - vasuclar, fenestrated endothelial cells.
negative charge BM
The foot processes of the podocyted are interdigitate. what are they bridged by?
what can gene defects in these cause?
a negative protein membrane
the loss of 2 of these proteins = glomerular disease
- nephrin gene –>congenital Finnish nephrotic syndrome
- CD2AP gene –> focal segmental glomerulosclerosis
where in the nephron is this? how can you tell?
Proximal convoluted tubule.
- Microvilli at apical end
- cuboidal epithelium
- round central nuclei
- many mitochondria for reabsorbtion of NaCl, proteins, polypeptides, AAs, glucose
where in the nephron is this?
loop of henle
thick = low cuboidal
thin = simple squamous
supplied by rich vasa recta
where in the nephron is the green star?
Distal convoluted tubule
- no(little) microvilli
- low cuboidal epithelium
- numerous mitochondria - regulates acid base by secreting H+ and absorbing HCO3 (via cellular carbonic anhydrase)
function of the proximal convoluted tubule?
reabsorb NaCl, proteins, polypeptides, AAs, glucose
function of the distal convoluted tubule
regulates acid base by secreting H+ and absoribing HCO3- via cellular carbonic anhydrase
regulates Na by exchanging urinary Na for bodily K - mediated by aldosterone
where in the nephron is this found?
collecting duct
- plumper cuboidal epithelium
- round central nuclei
what two cells are important in the collecting ducts?
- principle cells
- intercalated cells
which cells in the collecting duct respond to aldosterome and ADH?
principle cells
how do principle cells facilitate water reabsorbtion?
in response to ADh, they insert aquaporin-2 into membrane.
aquaporin-2 is a membrane channel for water reabsorbtion in the collecting ducts
(mutation of aquaporin 2 gene causes hereditary diabetes insipidus)
which cells in the collecting ducts exchange H+ for HCO3-?
INtercalated cells.
- alpha intercalated cells secrete acid
- beta interclated cells secrete bicarbonate
what are the two components of the juxtaglomerular apparatus and what do each contribute to?
- afferent arteriole → Granular cells→secrete renin in response to low bp
- Distal convoluted tubule → Macula Densa (packed enothelial cells) →senses NaCl conc and regulates tubuloglomerular feedback (also interact with granular cells)
3. lacis cells… unknown function
which blood vessel in the nephron is prone to ischaemia?
loop of henle deep in medullla
-far from glomerulus
the renal pelvis transmits filtrate from where to where
nephron to ureter
where would this epithelium be found?
urothelium - layer of umbrella over pseudostratified polygonal
found in the collection/drainage parts of the urinary tract
- renal pelvis
- ureters
- bladder
- male/female urethras
what makes up the layers of the ureters?
outer circular muscle
inner longitudinal muscle
no serosa
loos adventitia
where in the urinary tract is this?
ureters
(outer circular muscle, inner longitudinal = opp to GI)
where is this? what layers can be seen?
urothelium
laminal propria
muscularis mucosa
submucosa
muscularis propria
subseros and serosa
“valve”
male urethra epithelium?
- Prostatic urethra = urothelium
- membranous urethra = urothelium
- penile: psuedostratified epitheilium proximally
stratified squamous distally
female urethra epithelium?
proximally = urothelium
distally = squamous epithelium
what is the function of tje skin?
barrier to infection
waterproofing
thermoregulation
protect against trauma and UV
vit D synthesis
sensation
what are the four layers of the epidermis?
- stratum basale
- stratum spinosum
- stratum granulosum
- stratum corneum
which layer of the epidermis are melanocytes found?
basal layer. (statum basale)
what is the function of melanocytes?
synthesise melanin and transfer it to surrounding keratinocytes and melanosomes in response to MSH and ACTH stimulation
what is the function of melanin?
absorb UV light, protecting us from non-ionising radiation damage
what is the “prickle cell layer” and why is it called this?
the stratum spinosum - largest layer of epidermis.
made up of plump polygonal keratinocytes that are bound together by desmosones which are seen as interecellular adhesions that look like prickled between the cells.
most cells in the epidermis are?
keratinocytes
where would Langerhan’s cells be found and what is their function?
in the stratum spinosum of epidermis.
pale cytsoplasm.
antigen recogntion
Where would Merkel cells be found? what is their function?
Stratum spinosum of epidermis.
difficult to see.
sensory function
which layer of the epidermis is keratin formed?
stratum granulosum.
keratinocyted mature and fill with keratohyaline granules and die
which layer of the epidermis is acellular?
the stratum corneum - dead keratinised squames
what is the stratum lucidum? where in the body would it be found
layer between straum granulosum and stratum corneum.
found at palms and soles
what is the epidermal adnexae?
downgrowths of the epidermis into the dermis
where in the skin is this? what are the two arrows pointing to?
this is the epidermal adnexae.
top arrow = Hair follicle
bottom arrow = sebaceous gland
what type of secretion occurs at sebaceous glands? what are their purpose?
holocrine secretion = whole cell scretion.
sebaceous glands accompany hair follicules, lubricate and waterproof hairs.
where in the body would you find apocrine glands?
armpits, groin, genital and anus.
+ ceruminous glands in the ear
what type of gland is this? how can you tell?
apocrine gland:
-eosinophilic cytoplasm and SURFACE BUDDING.
what is apocrine secretion?
elements of the cystomplasm of cells secreted which bud off from luminal surface.
function of apocrine glands?
???? pheromones??
what typ of gland is this?
eccrine gland
where in the skin are eccrine glands found?
in the dermis
what TWO cell layers make up the eccrine gland?
inner secretory
outer myoepithelial
where are eccrine glands found in the body
everywhere.
eccrine (meroeccrine) secretion
what are the arrows pointing to? what is their function?
what is the space between them called?
rete pegs/ridges.
anchor epidermis onto underlying dermis.
space between = papillary dermis
label the layers of the dermis
(third arrow not dermis…what is it?)
papillary dermis (between rete pegs)
reticullar dermis
(subcutis)
name two sensory cells that can be found in the dermis
Meissner’s corpuscle and
Pacinian corpuscle
what is this? what does it detect? where is it found?
Pacinian corpuscle.
Vibration and tickle
deep dermis
what is this? what does it detect? where is it found?
Meissner’s corpuscle
fine touch
dermal papillae, esp in hairless skin
where in the skin is this? what is its function?
subcutis - whit adipose and fibrovascular septa
insulation, shock absorbtion, energy store
how does the male breast differ from the female breats histologicaly?
the male breast tissue comprises only of the duct system, (not lobules)
this is breast tissue. what are the three arrows pointing to?
top - lobules
middle - terminal duct
bottom - loose fibrouse connective tissue
what are the two layer of cells that line ducts and lobules in a breast?
outer myoepithelial = contractive
inner columnal epithelial = adapt to produce milk
breast is a collection of modified sweat glands.
how can you tell this breast is lactating?
the inner layers of secretory cells have become vacuolated
cant see columnar shape anymore.
what are the three layers that make up the capsule of the testes?
Tunica vaginalis
tunica albuginea
tunica vasculosa
out-in
what cells make up the tunica vaginalis?
flattened layer of mesothelial cells
what cells make up the tunica albuginea?
collagen fibres with some fibroblasts, myocytes, nerve fibres
what cells make up the tunica vasculosa?
loose connective tissue containing blood vessles and lymphatics
The testicular parenchyma is divided into how many lobules?
each lobule contains how many semineferout tubules?
Testicular parenchyma is divided into lobules by septa originating from the capsule - 250 lobules.
each lobule contain 1-4 semineferous tubules.
what is this structure?
semineferous tubules
what types of cells can be found in semineferous tubules?
- germ cells in varying stages of maturation
- sertoli cells (nuture)
these are germ cells at various stages of maruration,
label the arrows.
what are the different types of spermatogonia?
Type A - darkly stained (Ad)
Type A - pale stained (Ap)
Type B
where are the sertoli cells in this semineferous tubule?
where woudl leydig cells be found?
what is their function?
Present singly and in clusters in the interstitium between tubules.
Contain Reinke’s crystalloids = produce testosterone (not before puberty)
what is the function of the rete testis?
what cells are they comprised of?
Recieve luminal contents from semineferous tubules. Mixing chamber, possible secretions, reabsorbtion of protein
lined by simple squaous or low epithelium on a thick BM with cillia.
what cells are the efferent tubules comprised of?
ciliated and non ciliated simple columnar with interpsed basal cells = pseudostratified appearance
efferen ducts = same as straight ducts appearance
what cells make up the epididymis?
tall columnar cells with non motile stereocilla.
thick basement membrane and well defined muscular coat.
3 functions of epididymis?
absorb testicular fluid
phagocytosis of degenerative spermatazoa
secretes glycoproteins, sialic acid, glycerolphosphorylcholine = sperm maturation
what cells make up the vas deferens?
pseudostratified columnar epithelium with basal cells.
thick muscular wall of 3 layers.
which part of the prostate enlarges with age and which part is most susceptible to cancer?
peripheral = caner
central = enlarged with age
the prostate is covered by?
an ill-defined fibro-connective tissue capsule
where are these cells from?
prostate.
- glandular and non glandular
- ducts
- acini = 30-50 tubuloalveolar glands with convoluted edges.
all endocrine structures are made from glandular epithelium except?
posterior pituitary = neural tissue, axons and glia
the posterior pituitary secretes and stores?
oxytocin and ADH
what cells make up the anterior pituitary?
nested epithelial pituicytes
what are the 5 types of pituicytes?
somatotrophs (50%)
lactotrophs (25%)
corticotrophs (15-20%)
gonadotrophs (10%)
thyrothrophs (1%)
what are the most common type of pituicytes and what do they secrete?
somatotrophs (50%) - growth hormone
what do corticotrophs secrete?
ACTH
alpha - MSH
beta - lipoprotein
beta - endorphin
what pituicytes are these and where would they most likey be found?
somatotrophs
lateral wings of anterior pituitary
what pituicytes are these?
lactotrophs - hugging their neighbour so cute
what pituicytes are these and where would they most likey be found in anterior pituitary?
corticotrophs (round and basophilic)
median of glands
what pituicytes are these? what do they secrete?
gondotrophs - FSH, LH
what pituicytes are these?
thyrotrophs
also have processes but dont hug
nests of pituicytes are surrounded by?
reticulin
aside from pituicytes, what other cells can be found in the anterior pituitary?
sustentacular cells
what has happened to these pituitary cells?
pituitary adenoma - lost nesting architecture
what cells make up the pineal gland and how are they arranged?
pinealocytes - arranges in rosettes around central fibrillary towards capillary
why is pineal gland visible on xray?
calcium accumulates with age “brain sand”
what do these cells secrete?
pinealocytes - secrete melatonin
what cells are found in the thyroid?
follicular epithelal cells, around a colloid
and
C-cells inbeweteen the follicles
what are the labelled cells and what do they secrete?
top = BVs
C- cells = calcitonin (not visible)
Follicular cells = thyroxine
three cell types in the parathyroid?
cheif cells
oxyphils
adipocytes
what are the arrowed cells and what do they secrete?
left = cheif cells = PTH
right = oxyphil cell (more eosinophilic cyto) = increase with age, unknown function
what is the role of PTH?
raises serium Ca++
how can we differentiate between thyroid and parathyroid tissues?
calcium oxaloate in thyroid only
what is this structure and where is it found?
islet of langerhan
-pancrease
what are the 4 cells that can be found in the islets of langerhans?
Beta cells (70%) - INsulin
Alpha cells (20%) - glucagon
Delta cells (5-10%) - somatostatin
PP cells (1-2%) - pancreatic polypeptide
label the zones of the renal cortext
- Zona Glomerulosa
- Zona Fasciculata
- Zona Reticularis
where are mineralcorticoids produced?
zona glomerulosa of renal cortex
what is produced in the zona fasciculata?
cortisol
where are androgenic steroids produced?
zona reticularis of renal cortex
what cells are these, where are they found, and what do they produce?
chromaffin cells
adrenal medulla
adrenalin and noradrenalin
name come contractile cells of muscles
pericytes, myo-fibroblasts, myo-epithelial cells
myoblasts fuse to form multi-celled [?]
syncytium
myofibrils are formed from?
sarcomeres
a muscle fibre is fromed from many?
myofibrils
muscle fibres are clumped together to form?
fascicles
what are the connective tissues of muscles fibres?
why are muscle fibres/cells multinucleated?
in embryological development, individual myoblasts fuse to form an individual muscle fibre
describe skeletal muscle
volunatry muscle
striated
multinucleated
nuclei at edged
non branching
non IC discs
what are the striations in striuated muscle?
myofibrils in register : contractil proteins
myofibrils made from sarcomeres
what are the light and dark bankds in striated muscle?
light band = actin
dark band = myosin
what are the two types of sketal muscle?
Type 1 = energy from oxidative phosphorylation; slow twitch; fatique resistant
Type 2a = energy from oxidation and glycolysis
Type 2b = energy from glycolysis; fast twitch; fatique sensistive
what are these cells?
muscle spindles.
fibrocollagenous capsule, with intrafusal muscle fibre wrapped around gamma efferent nerve.
detect stretch
what types of fibres would attach muscle to bone over a wide area?
sharpey’s fibres
what would attache muscle to bone over a small area?
tendon
what is found in the extracellular matrix of bone?
Type I collagen
Glycoaminoglycans eg osteocalcin (strong affinity for Ca++)
Calcium hydroxyapaptite = mineralised
which cells do osteoblasts derive from?
embryonic mesenchyme (osteoprogenitor cells)
what do osteoblasts secrete?
osteoid = unmineralised bone
when osteoblasts become trapped in their oqwn matrix what do they become?
osteocytes = metabollically inactive
maybe resorb bone matrix/release calcium
how do entrapped osteocytes connect to surrounding cells to get their nutrients?
via canaliculi
what are osteoclasts derived from?
monocytes
which cells are multinucleated:
1. osteoblasts
2. osteoclasts
3. osteocytes
osteoclasts
what cells are these?
what is their function?
osteoclasts = resob bone
which cells sit in Howship’s lacunae?
osteoclasts
what cells are these?
what is their function?
osteoblasts = secrete ostiod (unmineralised bone)
RANK-L regulates the activity of what cells?
osteoclasts
if ostioid is layed down in parallel to eachother, what is it called?
lamellar, secondary bone
is ostioid is layed down haphazardly, what is it called?
woven, (primary bone)
explain what conditions are required for osteoid mineralisation to occur
- occurs when there is a hight concentration of calcium and phosphate ions
- requires osteocalcin (bind Ca++)
- requires alkaline phosphotase
label the arrows of thsi primary bone
where are osteons found?
secondary, lamellar bone
what type of bone is this?
what can be seen?
secondary, lamellar bone.
* osteons
* central haversian canal = Blood vessel
* Lamellar bone = osteocytes
which bones are formed from intramembranous bone formation?
which bones are formed from endochondrial bone formation?
Intramembranous = flat bones of the skull and clavical
Endochondiral = all other bones
outline intramembranous ossification
- From membranous template (no cartilagenous proformer)
- begins in utero, from primitive embryonic mesoderm
- mesenchymal stem cells –> osteoblasts –> isolated islands of bone –> expand and gaps become filled
outline endochondrial ossification
From hyaline cartliage precursor:
* chondrocytes produces cartilagenous precursor
* osteoblasts lay bone onto this cartilage = 1° ossification centre
* osteoclasts break down cartilage
* 1° OC is vascularised and periosteum begins to form
* some of 1°OC is broken down on inside = spongey = medullary cavity
* process repeats at end of bones = 2° OC
* some cartilage remains between the 1°OC and 2°OC = epiphyseal growth plate = fuse at end of puberty
label the reserve zones of endochondrial ossification
what happens in the proliferative zone / resting cartilage?
Chondrocytes divide rapidly and form columns within the matrix → zone of hyperplasia
This division is what pushes the diaphysis away from the epiphysis creating growth
what happens in the zone of hypertrophy?
Enlargement of chondrocytes leads to the beginning of calcification.
what happens in the zone of calcification?
Calcification of the matrix causes chondrocytes begin to die as it restricts nutrient diffusion. This leaves empty spaces.
what happens in the ossification zone?
Osteoblasts and vessels penetrate the empty spaces and creating new bone whilst osteoclasts break down the calcified cartilaginous matrix.
unlike hyaline cartilage which lines the articular surface of joints, synovium which lines the inside of the joint capsule is?
richly vascular, highly innervated
what is type A synovium?
phagocytes
What is type B synovium?
rich in rER
