Histology formative questions

Question 1

What diameter are neurone cell bodies?

Answer 1

20-65nm

Question 2

How many axon/dendritic processes does each motor neurone have?

Answer 2

0-5

Question 3

What is the diameter of a lymphocyte?

Answer 3

3.5-6.5um

Question 4

Are lymphocytes metabolically active?

Answer 4

Not really

Question 5

Do lymphocytes have lots of Nissl substance?

Answer 5

No, they are relatively dormant

Question 6

What is the average diameter of a thyroid follicle cell?

Answer 6

70nm

Question 7

In micrometres, how wide are muscle fibres?

Answer 7

10um

Question 8

What is chromatin?

Answer 8

Nuclear DNA plus proteins

Question 9

Where in the body might you find this epithelium?

1. Inside the gallbladder
2. Inside the mouth
3. Lining the inside of the small intestine
4. Lining the large airways
5. Lining the outside of the small intestine

Answer 9

5.Lining the outside of the small intestine. This is a simple squamous epithelium, single layer of flattened cells with cylindrical/elliptical nuclei of the type found lining the outside of the intestine.

Question 10

Which stain has been used in the image above to demonstrate the microvillous brush boarder?

1. Alcian blue
2. H+E
3. Iron haematoxylin
4. PAS
5. Perls

Answer 10

4. PAS. These are intestinal villi stained by the PAS procedure (magenta pink stain) and with haematoxylin (blue stain). The wine-glass shaped goblet cells stain dark pink as does the brush border. The nuclei of the columnar epithelial cells stain blue.

Question 11

Which of the statements concerning the image above is TRUE?

1. The cells with eosinophilic cytoplasm are a simple columnar epithelium
2. The cells with eosinophilic cytoplasm are ciliated
3. The cells with eosinophilic cytoplasm have a secretory function
4. The cells with haematoxyphilic cytoplasm have a secretory function
5. This is a sample from the large intestine

Answer 11

4.The cells with haematoxyphilic cytoplasm have a secretory function. The cells with eosinophilic cytoplasm in the centre of the image are forming a simple cuboidal epithelium and they are lining a duct within a salivary gland. They are not ciliated and do not have a secretory function. The cells with abundant haematoxyphilic cytoplasm around the periphery of the image are secretory cells.

Question 12

What is the typical thickness, in micrometres of these layers of cells?

1) 0.5
2) 0.7
3) 1.0
4) 1.5
5) 2.0

Answer 12

3) 1.0. This is a picture of lung showing air sacs (alveoli) whose walls are formed from capillaries and flattened squamous cells. The arrows point to areas of thin air-blood barrier which is typically 1 micrometre thick.

Question 13

Which of the following statements concerning the image above is FALSE?

1. All of the cells in this epithelium are in contact with the basement membrane
2. The epithelium contains some cells which secrete mucus
3. This epithelium is ciliated
4. This is a pseudostratified columnar epithelium
5. This is a stratified columnar epithelium

Answer 13

5. This is a stratified columnar epithelium.

This is pseudo-stratified columnar ciliated epithelium from the trachea. All of the epithelial cells are anchored to the basement membrane. The cells with pale cytoplasm are goblet cells that secrete mucus.

Question 14

The PAS procedure can be used to stain goblet cells and the brush border. What other structure will be stained by PAS?

1. Basement membrane
2. Mitochondria
3. Nuclei
4. Rough endoplasmic reticulum
5. Smooth endoplasmic reticulum

Answer 14

1. Basement membrane. The PAS procedure stains hexose sugar containing structures dark (magenta) pink. Typically the basement membrane immediately below and epithelium stains heavily because it contains hexose sugar containing glycoproteins.

Question 15

Apart from the respiratory tract, where else in the human body can cilia be found routinely?

1. Duodenum
2. Fallopian tube
3. Gallbladder
4. Retina
5. Urinary bladder

Answer 15

2. Fallopian tube. The only other location for a ciliated epithelium is the female genital tract, specifically the fallopian tube.

Question 16

In the epithelium above, where are the stem cells located?

1. Stratum basale
2. Stratum corneum
3. Stratum granulosum
4. Stratum lucidum
5. Stratum spinosum

Answer 16

1. Stratum basale. In the basal layer (Stratum basale). This is the layer most removed from the surface. From here daughter cells migrate up though the layers until they reach the surface, whereupon they are shed (desquamated)

Question 17

Which two proteins are principally involved in the generation of ciliary movement?

1. Actin and myosin
2. Actin and tubulin
3. Collagen and elastin
4. Tubulin and dyneine
5. Tubulin and myosin

Answer 17

4. Tubulin and dyneine. The main 2 proteins are tubulin and dyneine. Collagen and elastin are not contractile proteins, and actin and myosin while contractile are found in muscle cells.

Question 18

Which statement concerning the tight junctions in the epidermal lining of the gut is NOT one of their functions?

1. To allow the passage of water and glucose between the cells
2. To generate a concentration gradient across the epithelium
3. To hold cells together
4. To permit the passage of signal molecules from cell to cell
5. To prevent the passage of large molecules between the cells

Answer 18

4. To permit the passage of signal molecules from cell to cell. Tight junctions hold the cells together to prevent large molecules from passing between them and gaining access to the interior of the body. With tight junctions intact the epithelium acts as a barrier and can establish a gradient for the absorption of secretion of molecules from or into the gut. Only water and some selected small molecules (e.g. glucose) are able to breach this barrier. The passage of signal molecules from cell to cell is a function of gap junctions.

Question 19

Concerning the image above, which cell type is responsible for producing this type of connective tissue (stained brown)?

1. Elastoblasts
2. Elastocytes
3. Fibroblasts
4. Fibrocytes
5. Hepatocytes

Answer 19

3. Fibroblasts. This is a transverse section through the wall of a carotid artery stained for elastic tissue. The thick medial layer contains many concentric layers (sheets) of elastic tissue that stain brown (elastic Van Gieson stain). This elastic tissue replaces the smooth muscle found in this layer in muscular arteries. Like collagen, elastin is produced by fibroblasts. Elastoblasts, elastocytes and fibrocytes do not exist. Hepatocytes make fibrin.

Question 20

Which type of collagen forms the basement membranes of epithelia?

1. Type I
2. Type II
3. Type III
4. Type IV
5. Type V

Answer 20

4. Type IV

Basement membranes are formed from Type IV collagen.

Type I - Skin, bone, teeth, capsules of organs
Type II - Cartilage
Type III - Liver, kidney, spleen, arteries, uterus
Type IV - Basement membranes
Type V - Placenta

Question 21

The image above shows liver stained to reveal the fine reticular framework (stained black). What type of collagen is this?

1. Type I
2. Type II
3. Type III
4. Type IV
5. Type V

Answer 21

3. Type III. The coarser elements of this framework are often composed of Type I collagen but the fine framework is made of Type III collagen fibrils referred to histologically at reticular fibres or reticulin. The tissues of the reticulo-endothelial system (lymph nodes, spleen, liver etc.) are particularly rich in Type III collagen.

Question 22

What structural feature sets reticulin apart from other types of collagen

1. It can be readily seen on an H+E stained section
2. It can be stretched
3. It forms branched fibres
4. It forms straight linear fibres
5. It is produced by hepatocytes

Answer 22

3. It forms branched fibres. Unlike the other types of collagen, which tend to form in linear fibres, reticulin forms branched fibres. It is not easily seen on H+E stained sections and special stains are required. All types of collagen lack elasticity and therefore cannot be stretched. Reticulin is not produced by hepatocytes.

Question 23

Which of the following statements concerning the image above is TRUE?

1. This is dense elastic connective tissue
2. This is dense fibrocollagenous tissue
3. This is type III collagen
4. This is type IV collagen
5. This tissue contains branching collagen fibres

Answer 23

2. This is dense fibrocollagenous tissue. This image shows regularly arranged pink staining collagen fibres within a tendon. Fibroblast cells with blue staining nuclei are sandwiched between the fibres. Tendons contain type I collagen (type III is reticulin and type IV forms basement membranes). Type I collagen forms linear fibres.

Question 24

Which of the following statements concerning collagen formation is TRUE?

1. Individual collagen fibrils are formed from linear strands of tropocollagen lined end-to-end
2. The polypeptide chains within tropocollagen are wound into a beta-helix
3. Tropocollagen molecules are 300nm long
4. Tropocollagen subunits are assembled into fibrils prior to excretion from the cell
5. Tropocollagen subunits contain 5 linear polypeptide chains

Answer 24

3. Tropocollagen molecules are 300nm long. Individual collagen fibrils consist of overlapping linear strands of tropocollagen. Tropocollagen is synthesized within fibroblasts and other cell types. Tropocollagen molecules are secreted from cells and assembled into fibrils extra-cellularly. Overlapping of the linear tropocollagen units gives rise to characteristic banding to the collagen fibrils. Individual fibrils are often aligned side-by side to create larger collagen fibres of variable thickness. Each tropocollagen subunit is 300nm long and consists of 3 linear polypeptide chains, (usually two similar and one dis-similar chains) wound together in an alpha helix.

Question 25

What type of tissue is shown in this image? 1. Brown adipose tissue 2. Loose fibrous connective tissue 3. Liver tissue 4. Lung tissue 5. White adipose tissue

Answer 25

5. White adipose tissue. This is mature white adipose tissue. The cells appear empty because during processing the fat that is contained as a single large droplet has been extracted, leaving a white space. For this reason you might confuse this with lung tissue (where the white spaces contained air) or even with liver tissue (which can accumulate fat). In brown fat each cell contains multiple lipid droplets.

Question 26

Which of the following statements concerning adipose tissue is TRUE? 1. Brown fat is, in adults, most likely to be found between the shoulder blades 2. Brown fat is the most common type in adults 3. Mature adipocytes contain fat in the form of cholesterol 4. When lipids are withdrawn from adipocytes as a source of energy the fat droplet is typically entirely removed 5. White fat metabolises lipid to generate heat

Answer 26

1. Brown fat is, in adults, most likely to be found between the shoulder blades. Brown fat is widely distributed in the neonates but in adult life white fat is the predominant type found. In adults there is little brown fat but it can be found between the shoulder blades. White fat stores lipid in the form of triglyceride, and functions as a shock absorber, energy store and thermal insulator. Brown fat metabolises lipid to generate heat. When the lipids are extracted from white fat the lipid droplet gets smaller but is rarely entirely removed.

Question 27

Which of the following statements concerning smooth muscle is TRUE? 1. Smooth muscle cells are individually innervated 2. Smooth muscle cells are multinucleate 3. Smooth muscle cells contain visible striations when stained with iron haematoxylin 4. Smooth muscle cells contract faster than striated muscle cells 5. Smooth muscle cells have a centrally-placed nucleus

Answer 27

5. Smooth muscle cells have a centrally-placed nucleus. Smooth muscle cells have a centrally placed nucleus (they are single cells and do not form from syncytia of myoblasts and therefore only have a single nucleus). They are not individually innervated and contract more slowly than striated muscle cells. As their name suggests they have a smooth glassy eosinophilic cytoplasm that does not contain striations.

Question 28

Which of the statements concerning skeletal muscle is TRUE? 1. Epimysium is connective tissue that surrounds bundles of muscle fasciculi to create muscles 2. Fasciculi are small intracellular fibrils consisting of sarcomeres joined end to end 3. Endomysium is connective tissue that surrounds groups of muscle fibres to create fasciculi 4. Perimysium is connective tissue found as a delicate network between individual muscle fibres 5. Sarcomeres consist primarily of interdigitating filaments of fibrillin and dyneine

Answer 28

1. Epimysium is connective tissue that surrounds bundles of muscle fasciculi to create muscles

Question 29

Which of the following statements concerning the image is TRUE? 1. The dark bands are actin-rich 2. The sarcomeres are joined end to end AND side to side through the Z line 3. The section has been stained with elastic Van Geison 4. This is cardiac muscle 5. This is smooth muscle

Answer 29

2. The sarcomeres are joined end to end AND side to side through the Z line. This is a picture of skeletal muscle fibres (non-branching, striated) stained with iron haematoxylin to highlight the striations. The dark bands are myosin-rich and the light bands are actin-rich. The striations occur because the sarcomeres are in register, being joined end-to-end and side to side through the Z-lines.

Question 30

Which of the following statements concerning the image below is TRUE? 1. The fibres are rich in haemoglobin 2. The muscle cells are individually innervated 3. The muscle fibres have their own innate contractility 4. This muscle can function anaerobically 5. The sarcomeres are joined end to end AND side to side through the Z line

Answer 30

3. The muscle fibres have their own innate contractility. This is cardiac muscle (branched fibres, no striations). Cardiac myocytes are not individually innervated. They have their own innate contractility and will go on beating without a nerve supply. But for purposes of co-ordination and effective contraction (pumping) they rely on stimuli arising from the sino-atrial and atrio-ventricular nodes. They do not function in an anaerobic environment. Muscle cells do not contain haemoglobin.

Question 31

Which of the following statements is TRUE? 1. Cardiac muscle cells contain myosin but not actin 2. In skeletal muscle, myofibrils are secreted by the cells and assembled extracellularly 3. Only the A and I bands of skeletal muscle can be resolved with a light microscope 4. Skeletal muscle cells do not contain mitochondra 5. Some striated muscle cells are rich in myoglobin

Answer 31

5. Some striated muscle cells are rich in myoglobin. Some skeletal muscles are rich in myoglobin. Like haemoglobin, myoglobin can bind oxygen into the cell, allowing it to be released when needed. All myofibrils are intracellular and all muscle types contain mitochondria. All bands of the sarcomeres are within the resolving power of a light microscope.

Question 32

In cardiac muscle, contraction is regulated by the cytosolic concentration of which metal? 1. Calcium 2. Magnesium 3. Potassium 4. Sodium 5. Strontium

Answer 32

1. Calcium. Muscle contraction occurs when the actin and myosin filaments within the sarcomeres cross over one another. Tropomyosin is a long rod-like protein that wraps itself around the actin filaments to stabilise and stiffen it. Troponin I is bound to tropomyosin and serves to regulate the binding of actin to myosin. An influx of calcium ions into the cell produces a conformational change in the shape of troponin I, allowing myosin access to the actin and permitting contraction.

Question 33

Concerning the muscle shown in the image, which statement is FALSE? 1. At rest these cells contain little intracellular calcium 2. Each cell is formed by the fusion of hundreds of precursor cells 3. Each muscle fibre contains hundreds of parallel myofibrils 4. There is a resident population of precursor cells which can divide to produce new muscle cells after tissue damage 5. The sarcomeres are joined end to end but not side to side at the Z-plates

Answer 33

5. The sarcomeres are joined end to end but not side to side at the Z-plates. This is skeletal (striated) muscle cut transversely. You can tell this is the case because the blue-staining nuclei are located at the edge of the muscle fibres. All of the statements are true, with the exception of E. In striated muscle the sarcomeres are joined both end-to-end and side-to-side.

Question 34

Concerning the image above, which statement is TRUE? 1. A is an axon within a Schwann cell 2. A is a Schwann cell nucleus 3. B is a nerve cell body 4. B is a Schwann cell nucleus 5. C is a myelinated axon

Answer 34

2. A is a Schwann cell nucleus. A is a Schwann cell nucleus, B a myelinated axon, C is an axon (unmyelinated) within a Schwann cell and D is myelin.

Question 35

Which substance is the predominant component of myelin in the peripheral nervous system? 1. Myelin-associated glycoprotein 2. Myelin basic protein 3. Peripheral myelin protein 4. Proteolipid protein 5. Sphingomyelin

Answer 35

5. Sphingomyelin. Myelin is membranous in nature and consists of a bilipid (phospholipid) layer with proteins inserted into it and spanning between the layers. Sphingomyelin is the predominant phospholipid. There are a number of unique proteins and lipoproteins including proteolipid protein, myelin basic protein, PO protein and peripheral myelin protein whose abnormal expression results in several recognisable diseases and conditions. Myelin-associated glycoprotein is found in the central nervous system on the surface of oligodendrocytes.

Question 36

The image shows a peripheral nerve which has been stained to demonstrate the myelin. Which staining method has been used. 1. H+E only 2. Iron haematoxylin 3. Masson's trichrome 4. Osmium tetroxide and H+E 5. Perls Prussian blue reaction

Answer 36

4. Osmium tetroxide and H+E. This is part of a peripheral nerve cut in transverse section and treated with osmium tetroxide (brown/black) and H&E. Small circular myelinated axons can be clearly seen within each nerve fibre

Question 37

What term is used to describe the connective tissue sheath that binds axons together to form a nerve? 1. Endoneurium 2. Epineurium 3. Exoneurium 4. Paraneurium 5. Perineurium

Answer 37

5. Perineurium.The connective tissue between individual axons is known as the endoneurium and that which binds nerve fibres together to form a nerve is called the epineurium.

Question 38

The image shows a peripheral nerve which has been stained to demonstrate the myelin. What conduction speeds are typical of these myelinated axons? 1. 0.5 - 5.0 metres per second 2. 1.0 - 10.0 metres per second 3. 1.0 - 20.0 metres per second 4. 10.0 - 50.0 metres per second 5. 10.0 - 100.0 metres per second

Answer 38

5. 10.0 - 100.0 metres per second. Conduction velocity depends on the diameter of the axon and whether or not it is myelinated. Unmyelinated axons have conduction velocities of between about 1 and 20 metres per second while myelinated axons have velocities between 10 and 100 metres per second. Note too that myelinated axons have faster conduction velocities than unmyelinated axons 100 times their diameter.

Question 39

What conduction speeds are typical of unmyelinated axons? 1. 0.5 - 5.0 metres per second 2. 1.0 - 10.0 metres per second 3. 1.0 - 20.0 metres per second 4. 10.0 - 50.0 metres per second 5. 10.0 - 100.0 metres per second

Answer 39

3. 1.0 - 20.0 metres per second. Conduction velocity depends on the diameter of the axon and whether or not it is myelinated. Unmyelinated axons have conduction velocities of between about 1 and 20 metres per second while myelinated axons have velocities between 10 and 100 metres per second. Note too that myelinated axons have faster conduction velocities than unmyelinated axons 100 times their diameter.

Question 40

What type of nerve cell is this? 1. Bipolar 2. Multi-polar 3. Pseudo-unipolar 4. Unipolar

Answer 40

2. Multi-polar(it has more than two processes coming from the cell body). The other main types are unipolar (1 process), pseudo-unipolar (apparently only 1 process) and bipolar (2 processes) neurones

Question 41

Which statement concerning this image is FALSE? 1. Release of the contents of the small spherical structures (centre of the image) is mediated by voltage-gated sodium channels 2. Release of the contents of the small spherical structures is via diffusion through the membrane of the cell 3. This is a synapse 4. The membranes of the small spherical structures become transiently incorporated into the cell membrane 5. The small spherical structures seen were derived solely from transport down the axon

Answer 41

1. Release of the contents of the small spherical structures (centre of the image) is mediated by voltage-gated sodium channels. This is a synapse and the small spherical structures are synaptic vesicles. Their contents is released via diffusion and their membranes do fuse with the presynaptic cell membrane but release is mediated by voltage-gated calcium channels.

Question 42

Which of the following is NOT found within an axon? 1. Actin 2. Dynein 3. Microtubules 4. Neurofilaments 5. Tubulin

Answer 42

1. Actin. Microtubules, consisting of assemblies of tubulin and dynein are closely associated with the process of axonal transport - the transport of vesicles from the Golgi apparatus in the neurone cell body to the end of the axon and back again - anterograde and retrograde transport respectively. Neurofilaments are a class of intermediate filament unique to neurones. They are part of the cytoskeleton of nerve cells and seem to play a major part in the determination of axon diameter.

Question 43

Which statement concerning the structure arrowed in the image is FALSE? 1. It is a node of Ranvier 2. It is the junction between two axons 3. The axon is bare of myelin at this point 4. There are a large number of gated Na+ channels at this point 5. Tongues of Schwann cell cytoplasm are present on the axon

Answer 43

2. It is the junction between two axons. This is a high magnification view of nerve fibres cut longitudinally. The section has been treated with osmium tetroxide (brown/back) and stained with H&E. It shows about 20 axons running across the picture, some of which display constrictions known as nodes of Ranvier. These represent the junction between two Schwann cells and the axon is bare of myelin at this point, though tongues of Schwann cell cytoplasm are present. The axon at the node of Ranvier contains most of the gated Na+ channels of the axonal cell membrane. There are no gated channels in the intermodal region beneath the myelin.

Question 44

A 27-year-old woman is found to have the cells above in her blood. What is the most likely explanation? 1. She has diabetes mellitus 2. She has leukaemia 3. She has lymphoma 4. She has septicaemia 5. She is bleeding

Answer 44

5. She is bleeding. These are reticulocytes. Red blood cells are formed in the bone marrow. They normally lose their nuclei and cytoplasmic organelles before they are released into the blood stream. In some cases however immature red cells still containing some visible ribosome remnants may be released into the blood stream. These cells are referred to as reticulocytes. They normally constitute less than 1% of the circulating red cell population. To find this many reticulocytes is abnormal. The most likely explanation is that she has severe blood loss.

Question 45

What cell type is shown in the image? 1. Basophil 2. Eosinophil 3. Macrophage 4. Mast cell 5. Neutrophil

Answer 45

5. Neutrophil. These are neutrophil polymorphs. You can identify them by their multi-lobulated nucleus.

Question 46

Which of the statements concerning the image above is TRUE? 1. This cell type becomes more common in the blood in parasitic infections 2. This cell type has more microbicidal activity than neutrophils 3. This cell type is more common in the blood in the afternoons than the mornings 4. This cell type secretes a substance that promotes mast cell degranulation 5. This cell type secretes histamine

Answer 46

1. This cell type becomes more common in the blood in parasitic infections. This is an eosinophil (prominent eosinophilic granules and a bi/tri-lobed nucleus. These cells appear in greater numbers in the mornings than in the afternoons (diurnal variation) and their numbers increase greatly in patients with parasitic infections. They act to counter the effects of mast cells, preventing mast cell degranulation and countering the effects of histamine.

Question 47

Which statement regarding the cell type shown in the image is TRUE? 1. This cell type becomes more numerous in the blood of patients receiving corticosteroids 2. This cell type may be found within the alveolar air spaces of the lung 3. This cell type mounts the initial cellular response in acute inflammation 4. This cell type secretes antibodies 5. This is a lymphocyte

Answer 47

2. This cell type may be found within the alveolar air spaces of the lung. This is a picture of a macrophage (kidney-shaped nucleus, no granules). They are found circulating in the blood and are also present in the alveolar air spaces. Many of these cells enter and take residence in the connective tissues, when they become known as tissue fixed macrophages or histiocytes. The liver and spleen have a population of fixed macrophages. Macrophages are phagocytic cells and while they are found in acute inflammation they arrive after the neutrophils. Their numbers are depressed by corticosteroids.

Question 48

Which of the following statements concerning the image below is TRUE? 1. The function of these cells is unknown 2. These are cells with a high nuclear/cytoplasmic ratio 3. These are fragments of cells that are found in the bone marrow 4. These are fragments of erythrocyte nuclei 5. These are nucleated cells

Answer 48

3. These are fragments of cells that are found in the bone marrow. Platelets are small fragments of cells without a nucleus which are derived from multi-nucleate megakaryocytes in the bone marrow. They contain a range of cell organelles, including 4 different types of granule. They play an important role in haemostasis.

Question 49

The image shows the wall of what type of vessel? 1. Arteriole 2. Elastic artery 3. Muscular artery 4. Vein 5. Venule

Answer 49

3. Muscular artery. This is the wall of a large muscular artery showing 3 distinct layers. A thin intima to the left, a broad densely packed media, composed of smooth muscle in the centre and an adventitia to the right composed of strands of collagen and elastic fibres.

Question 50

Which of the following is NOT an elastic artery? 1. Aorta 2. Common carotid artery 3. Dorsalis pedis artery 4. Innominate artery 5. Subclavian artery

Answer 50

3. Dorsalis pedis artery. In the major arterial vessels close to the heart (aorta, subclavian arteries, common carotid arteries) the muscle of the media is heavily reinforced with concentric sheets of elastic tissue. The innominate artery arises from the aorta and branches to become the right common carotid artery and right subclavian artery. The dorsalis pedis is a muscular artery.

Question 51

This is an image of what type of vessel? 1. Arteriole 2. Capillary 3. Lymphatic 4. Vein 5. Venule

Answer 51

1. Arteriole. This has to be an arteriole - it has two layers of smooth muscle in its wall and therefore cannot be any of the others.

Question 52

This is mature adipose tissue containing small vessels. Which statement is TRUE? 1. These vessels are 10-15 micrometres in diameter 2. These vessels contain scattered contractile cells in their walls 3. These vessels lack a basement membrane 4. These vessels lack an endothelium 5. These vessels transport lymph

Answer 52

2. These vessels contain scattered contractile cells in their walls. These are capillaries. Capillary walls comprise endothelium, a basement membrane and scattered contractile cells called pericytes. Capillaries are 5-10 micrometres in diameter and therefore the smallest are smaller than the diameter of erythrocytes. You can tell that these are not lymphatics because the vessels contain erythrocytes.

Question 53

Which of the following statements is TRUE? 1. All blood passes through a capillary bed on its way around the body 2. Nitric oxide causes the walls of arterioles to contract 3. The adventitia of arterioles is mostly collagen and elastic tissue 4. The aorta contains abundant smooth muscle in the media 5. Von Willebrand factor (released by endothelium) inhibits platelet adhesion

Answer 53

3. The adventitia of arterioles is mostly collagen and elastic tissue. The adventitia of arteries and arterioles is mostly collagen and elastic tissue. There are arterio-venous shunts which mean that not all blood has to pass through the capillaries. These shunts allow organs to control their perfusion. Nitric oxide causes vasodilatation and von Willebrand factor promotes platelet adhesion.

Question 54

Which of the following cells lies with and are unable to migrate through the matrix of a cartilage? 1. Chondroblast 2. Chondrocyte 3. Fibroblast 4. Osteoblast 5. Osteocyte

Answer 54

2. Chondrocyte. Cartilage and bone are rigid forms of connective tissue. The two are closely inter-related, being derived from a common undifferentiated mesenchymal cell in the embryo. Furthermore, some bones are initially formed as cartilage and in later life some cartilages in the body become ossified. In cartilage, the cells are embedded in a dense glycosaminoglycan rich matrix containing variable amounts of collagen and elastic tissue. This is flexible, compressible and hardwearing. Cartilage is formed initially by chondroblasts. These eventually become trapped within the matrix and mature into chondrocytes. The trapped cells are unable to migrate through the matrix

Question 55

Which statement about the image is FALSE? 1. The cells in this cartilage synthesised the matrix that surrounds them 2. The matrix of this cartilage binds large amounts of water 3. The matrix of this cartilage contains abundant glycosaminoglycans 4. This cartilage contains fine fibrils of elastin 5. This is typical of the cartilage of the epiglottis

Answer 55

5. This is typical cartilage of the epiglottis. This is hyaline cartilage, typical of that found in the knee. Hyaline cartilage has a glycosaminoglycan-rich matrix containing fine fibrils of collagen and elastin, that is secreted by chondroblasts. The matrix surrounds the chondroblasts and once encased, they are known as chondrocytes. Hyaline cartilage contains a lot of water, which is released on compression and rapidly reabsorbed when the pressure is removed. The epiglottis contains elastic cartilage.

Question 56

Which of the statements concerning the image below is TRUE? 1. This is decalcified cortical (compact) bone 2. This is dense fibrous connective tissue 3. This is fibrous cartilage 4. This is osteoid 5. This is the inner part of an intervertebral disc

Answer 56

3. This is fibrous cartilage. This is part of the outer casing of an inter-vertebral disc showing fibrous cartilage. Fibrocartilage has large amounts of collagen fibres in its matrix, sometimes organised into sheets or laminae. Fibrocartilage occurs in the inter-vertebral discs that lie between the vertebral bodies of spinal column. Here they absorb much of the force applied to the column and permit it to flex.

Question 57

Which of the following statements concerning cartilage is TRUE? 1. Chondrocytes receive most of their nutrients by diffusion through the matrix 2. Elastic cartilage cannot be fractured 3. Fibrous cartilage contains type III collagen 4. Once embedded in matrix chondrocytes do not divide 5. The septum of the nose is made partly of elastic cartilage

Answer 57

1. Chondrocytes receive most of their nutrients by diffusion through the matrix. Chondrocytes do receive most of their nutrients by diffusion through the matrix. They continue to divide. Elastic cartilage can be fractured, albeit with some difficulty. Fibrous cartilage contains collagen types I and II. The septum of the nose is partly made of hyaline cartilage.

Question 58

This section has been demineralised. What type of collagen predominates? 1. Type I 2. Type II 3. Type III 4. Type IV 5. Type X

Answer 58

1.. Type I. Bone is composed of type 1 collagen

Question 59

Which of the following is NOT involved in the mineralisation of bone? 1. Alkaline phosphatase 2. Hydroxyapatite 3. Osteocalcin 4. Pyrophosphatase 5. Sulphuric acid

Answer 59

5. Sulphuric acid. All of these substances play a role in the mineralisation of bone, with the exception of sulphuric acid which can be used to demineralise bone in the laboratory. Alkaline phosphatise, abundant in osteoblasts, increases the local concentrations of calcium ions and phosphate ions. Hydroxyapetite is the mineral found in bone. Osteocalcin is a glycoprotein that binds extracellular calcium ions and pyrophosphatase cleaves phosphate ions from larger molecules.

Question 60

Which of the following statements is TRUE? 1. Mineralised bone is dead tissue 2. Osteoblasts have eosinophilic cytoplasm 3. Osteoclasts contain significant quantities of lysosomal enzymes 4. Osteocytes are not in direct contact with one another 5. Osteoid is secreted by fibroblasts

Answer 60

3. Osteoclasts contain significant quantities of lysosomal enzymes. Osteoclasts digest bone. To do this they require significant quantities of lyzosomal enzymes. These are stored within the cytoplasm of the cells and stain intensely with eosin. Hence the dark pink colouration. Osteocytes have delicate filopodia which connect the cells together, aiding the passage of nutrients through the bone. Osteoid is secreted by osteoblasts, which have basophilic cytoplasm.

Question 61

What are these two rows of purple-staining cells? 1. Chondroblasts 2. Chondrocytes 3. Fibroblasts 4. Osteoblasts 5. Osteoclasts

Answer 61

4. Osteoblasts. This is developing membrane bone stained with H&E . The pale blue plate of bone has aggregations of purple osteoblasts on each surface.

Question 62

Which of the following is NOT a potential complication of atheroma? 1. Aneurysm formation 2. Amyloid deposition 3. Dystrophic calcification 4. Impaired blood flow 5. Thrombus formation

Answer 62

2. Amyloid deposition. Atheroma is a degenerative hardening and furring of blood vessels, seen principally in arteries. It occurs as a result of damage to the vascular endothelium and results in the accumulation of lipid in vessel walls. Atheromatous plaques narrow the vessel, impairing blood flow. According to Virchow's triad, changes in the vessel wall can result in thrombus formation. Atheromatous plaques weaken the vessel, leading sometimes to aneurysm formation and they can calcify. Amyloid is an inert protein deposited in blood vessels, typically as a result of chronic inflammatory processes, but it is not associated with atheroma.

Question 63

Which of the following cell types form the lining of the mitral valve? 1. Cardiac myocytes 2. Fibroblasts 3. Mesothelial cells 4. Pericytes 5. Vascular endothelial cells

Answer 63

5. Vascular endothelial cells. The inner lining of the heart (endocardium), which also lines the surfaces of the heart valves is composed of vascular endothelial cells. The outer surface of the heart (pericardium) is lined by flattened layer of mesothelial cells. Pericytes are found on the outside of capillaries and veins. Cardiac myocytes form the heart muscle itself and are not present within the valves. Fibroblasts are present within valves and produced the fibro elastic tissue of which they are composed.

Question 64

Which of the following is NOT a function of these structures (green arrows)? 1. Anchor the actin fibres of the sarcomeres to each 2. Bind cardiac myocytes together 3. Denote the boundary between adjacent myocytes 4. Electrically couple cardiac myocytes 5. Permit cardiac conduction

Answer 64

5. Permit cardiac conduction. These are intercalated discs which are specialised cell junctional systems that anchor actin fibres of the sarcomeres to each end of the cell, bind cardiac myocytes together with desmosomes and denote the end boundaries of cardiac myocytes. Cardiac conduction is a function of Purkinje cells.

Question 65

Which of the following statements is TRUE? 1. Firing of the atrioventricular node regulates the cardiac rate 2. The atrioventricular node is composed of specialised muscle fibres 3. The atrioventricular node is located at the apex of the left ventricle 4. The Sino atrial node is located in the wall of the left atrium 5. The Sino atrial node is composed of mesothelial cells

Answer 65

2. The atrioventricular node is composed of specialised muscle fibres. The atrioventricular node is composed of specialised muscle fibres. The Sino atrial node, located in the wall of the right atrium, adjacent to the superior vena cava, regulates the heart rate and is also composed of specialised muscle fibres. The atrioventricular node is located beneath the endocardium of the medial wall of the right atrium, just in front of the opening of the coronary sinus and immediately above the tricuspid valve ring.

Question 66

Which of the following statements concerning these cells found within the wall of the heart is TRUE? 1. The cytoplasm contains abundant lipid 2. These are Pericytes 3. These are specialised nerve cells 4. These cells conduct the cardiac impulse 5. These cells contain abundant myofibrils

Answer 66

4. These cells conduct the cardiac impulse. These are Purkinje fibres, stained using the periodic acid Schiff procedure which highlights the abundant glycogen that is present within the cytoplasm. Purkinje fibres are specialised cardiac myocytes which contain few myofibrils. Their function is to conduct the cardiac impulse, resulting in coordinated contraction of the heart.

Question 67

Which of the following statements concerning the general structure of arteries and veins is TRUE? 1. The intima contains densely packed collagen and elastin fibres 2. The intima is lined by pericytes 3. The myo-intimal cells have fibrogenic potential 4. The walls of arteries and veins have four histological layers 5. Veins have thicker walls than their corresponding arteries

Answer 67

3. The myo-intimal cells have fibrogenis potential. Arteries and veins have walls with three distinct histological layers - an innermost intima comprising endothelial cells resting on loose connective tissue with fibrogenic potential, a central medial layer which contains smooth muscle, elastic and collagen fibres invariable portions, and an outer adventitia containing densely packed collagen and elastin fibres. Pericytes are found lining the outside of veins.

Question 68

What type of blood vessel is this? 1. Arteriole 2. Capillary 3. Elastic artery 4. Muscular artery 5. Vein

Answer 68

4. Muscular artery. This is a muscular artery, identified by the well-defined medial layer that is composed of circumferentially arranged smooth-muscle cells. There are more than three layers of cells in the media and so this is not an arteriole. The media can be seen to be separated from the intima by a layer of wavy internal elastic fibres known as the internal elastic lamina. This is much too large to be a capillary - these are typically smaller than the diameter of a red blood cell.

Question 69

Which types of vessel are shown in this image? 1. Arteries and veins 2. Arterioles and capillaries 3. Arterioles and venules 4. Capillaries and lymphatics 5. Venules and lymphatics

Answer 69

3. Arterioles and venules. These are small arterioles accompanied by thinner walled venules. Arterioles, convey blood towards the capillary bed and arbitrarily defined as small diameter arterial vessels with three layers or fewer of smooth-muscle in their medial layer. Note that the lumen of the arterioles is smaller than the lumen of the accompanying venules. Capillaries have a diameter smaller than that of a red blood cell.

Question 70

Which of the following statements is NOT a function of vascular endothelial cells? 1. Active transport of molecules across the cytoplasm 2. Modulation of blood coagulation 3. Secretion of an internal elastic lamina 4. Secretion of nitric oxide 5. Secretion of prostacyclin

Answer 70

3. Secretion of an internal elastic lamina. Vascular endothelial cells have highly specialised endocrine, exocrine, cell adhesion, clotting and transport functions. They do not however secrete the internal elastic lamina.

Question 71

Which of the following statements concerning these vessels is TRUE? 1. They are the principal route by which lymphocytes migrate around the body 2. They are similar in structure to arteries and arterioles 3. They are veins 4. They do not contain valves 5. They contain plasma

Answer 71

5. They contain plasma. These are lymphatic vessels, which drain plasma from tissues back into the circulation. This plasma appears pink in H&E stained sections. Similar in structure to capillaries and veins, their walls are composed mainly of connective tissue with occasional smooth-muscle cells. The pressure within these vessels is low and so the walls are not generally as thick as veins. Although not seen in this image, lymphatic vessels do contain valves. While a small number of lymphocytes may be present within the lumen the principal route of lymphocyte migration is via the blood vessels.

Question 72

This tissue is from which part of the respiratory tract? 1. Bronchus 2. Lung 3. Nose 4. Trachea 5. Vocal cord

Answer 72

3. Nose. This is olfactory epithelium stained with H&E and Alcian Blue. The epithelium is pseudo-stratified columnar epithelium. Immotile stereocilia protrude from the surface. Most of the cells are supporting cells but between them are sensory cells capable of detecting odours. The basal cells contain pigment granules. Under the epithelium are blue staining serous glands whose secretions flush the surface removing stale smells. Large oval unmyelinated nerve bundles are also evident.

Question 73

This tissue is from which part of the respiratory tract? Bronchus Lung Nose Trachea Vocal cord

Answer 73

3. Nose. This is also tissue from the nose, this time from the nasal septum. The tissue has been stained with H&E and Alcian blue. The picture shows central plate and bone with the respiratory epithelium on either side (top left and bottom right). Thin-walled blood vessels can be seen within the connective tissue between the epithelial and the bone. Mucus containing goblet cells stain bright blue.

Question 74

Which of the following is present within the walls of bronchi but not in the walls of bronchioles? 1. Arterioles 2. Cartilage 3. Lymphoid nodules 4. Respiratory epithelium 5. Smooth muscle

Answer 74

2. Cartilage. The structure of bronchioles and bronchi are very similar. Both are lined by respiratory epithelium and have walls which contain smooth-muscle and lymphoid nodules. However bronchioles do not contain hyaline cartilage within their walls and instead have a prominent band of smooth muscle. (Smooth-muscle is also present within the walls of bronchi).

Question 75

Which of the following statements is TRUE? 1. Terminal bronchioles are surrounded by a sphincter of skeletal muscle 2. Terminal bronchioles are the largest airways concerned with gas exchange 3. Terminal bronchioles contain cartilage within their walls 4. Terminal bronchioles contain Clara cells 5. Terminal bronchioles secrete surfactant

Answer 75

5. Terminal bronchioles contain Clara cells. Terminal bronchioles are the last part of the bronchial tree and are solely concerned with air conduction. They are surrounded by a sphincter but this is composed of smooth muscle. They are not concerned with gas exchange and they do not secrete surfactant. The terminal bronchioles are the sites where Clara cells are most abundant.

Question 76

Which of the following statements concerning Clara cells is TRUE? 1. They are ciliated 2. They are most abundant in the alveoli 3. They contain abundant smooth endoplasmic reticulum 4. They contain few mitochondria 5. They produce mucus

Answer 76

3. They contain abundant smooth endoplasmic reticulum. Clara cells are most abundant in the terminal bronchioles. The function of these cells is not fully known but it has been suggested that because they contain many large mitochondria, abundant smooth endoplasmic reticulum and some secretory granules that they have synthetic and secretory function. They do not produce mucus. It has been proposed that Clara cells protect against the deleterious effects of inhaled toxins and carcinogens and protect against emphysema. They may play a role in surfactant production or elimination and they are probably a stem cell capable of producing other types of bronchial epithelial cells. Clara cells are not ciliated and do not produce mucus.

Question 77

Which of the following statements concerning the air-blood barrier is TRUE? 1. It does not contain type IV collagen 2. It includes fibroblasts 3. It includes surfactant 4. It is between two and six micrometres thick 5. It is formed predominantly by type II pneumocytes

Answer 77

3. It includes surfactant. Gases passing across the air blood barrier must defuse across five layers - surfactant, an alveolar cell, a basement membrane, capillary endothelium and a red cell membrane. You should be aware by now that basement membranes are composed of type IV collagen. The alveolar cell is a type I pneumocyte. The normal air blood barrier is only 0.2 to 0.6 micrometres thick.

Question 78

What is the structure labelled X in the picture? 1. Basement membrane 2. Nerve axon 3. Red blood cell 4. Stratified squamous epithelium 5. Taste bud

Answer 78

5. Taste bud. This is a tastebud. The surrounding tissue is stratified squamous epithelium.

Question 79

What is shown in this picture? 1. Pancreatic acini and ducts 2. Parotid gland acini and ducts 3. Sublingual salivary gland acini and ducts 4. Submandibular salivary gland acini and ducts 5. Sweat gland acini and ducts

Answer 79

3. Sublingual salivary gland acini and ducts. This tissue comprises acini lined by cells with abundant optically clear cytoplasm and basally located nuclei, with the associated ducts that are lined by a cuboidal to columnar epithelium. Mucin is optically clear, and these are mucinous acini. No serous secretory cells (which have a granular eosinophilic cytoplasm) are seen. This must therefore be the sublingual salivary gland, which has purely mucinous secretions. (The parotid gland is serous, and the submandibular gland is mixed seromucinous.)

Question 80

What is shown in this picture? 1. Pancreatic acini 2. Parotid gland acini 3. Sublingual salivary gland acini 4. Submandibular salivary gland acini 5. Sweat gland acini

Answer 80

4. Submandibular salivary gland acini. This tissue comprises, at the top of the picture, acini lined by cells with abundant optically clear cytoplasm and basally located nuclei, with the associated ducts that are lined by a cuboidal to columnar epithelium. Mucin is optically clear, and these are mucinous acini. Serous secretory cells (which have a granular eosinophilic cytoplasm) are also seen in the bottom half of the picture. This must therefore be the submandibular salivary gland, which is a mixed seromucinous gland.

Question 81

This is a representative picture of a salivary gland. Which cranial nerve runs through this gland? 1. Facial 2. Glossopharyngeal 3. Hypoglossal 4. Trigeminal 5. Vagus

Answer 81

1. Facial. Only secretory acini are seen. This must be the parotid gland. The facial nerve runs through, but does not innervate, the parotid gland. This nerve may be damaged during surgery on the parotid, resulting in ipsilateral facial weakness.

Question 82

Which of the following statements concerning the cells found on and within the tongue is TRUE? 1. Lymph nodules are most commonly found in the anterior third of the tongue 2. The extrinsic muscles of the tongue attach only to the fibrous connective tissue underlying the mucosa 3. The tongue contains mixed seromucinous salivary glands 4. The tongue is made of smooth muscle 5. The upper surface of the tongue is covered by non-keratinised stratified squamous epithelium

Answer 82

3. The tongue contains mixed seromucinous salivary glands. The tongue is mostly muscle - skeletal muscle. It does contain mixed seromucinous salivary glands and lymph nodules, but the latter are most commonly found in the posterior third. The intrinsic muscles of the tongue attach only to the fibrous connective tissue underlying the mucosa, whereas the extrinsic muscles attach to the lower jaw. The under-surface (ventral surface) of the tongue is typically covered by non-keratinised stratified squamous epithelium but the dorsal (upper) surface of the tongue is exposed to more abrasion and undergoes keratinisation.

Question 83

Which of the following statements concerning taste buds and the papillae which bear them is TRUE? 1. A V-shaped row of filiform papillae marks the boundary between the anterior two-thirds and posterior third of the tongue 2. Circumvallate papillae do not bear taste buds 3. Fungiform papillae are the most common type 4. Taste buds are found embedded into the muscle of the tongue 5. Taste buds are embedded into the lateral sides of the papillae

Answer 83

5. Taste buds are embedded into the lateral sides of the papillae. Taste buds are found embedded into the stratified squamous epithelium that lines the sides of the papillae. (They are not embedded into the underlying muscle.) All papillae bear taste buds. The circumvallate papillae form a V-shape that marks the boundary between the anterior two-thirds and posterior third of the tongue (and bear taste buds that sense bitter taste). Filiform papillae are the most numerous, and cover the whole of the anterior two-thirds of the tongue. Fungiform papillae are less numerous and are found on the tip and sides of the tongue. The locations of the different types of papillae gave rise to the notion of 'tongue maps', indicating which of the senses of taste are sensed on which parts of the tongue. It is now believed that these maps are wrong, and that all taste sensations are detected on all parts of the tongue.

Question 84

This is part of the wall of the stomach. Which statement regarding the cells indicated by red arrows is TRUE? 1. They are abundant in the gastric antrum 2. They are oxyntic cells 3. They absorb vitamin B12 4. They secrete sodium hydroxide 5. They secrete vitamin B12

Answer 84

2. They are oxyntic cells. These are oxyntic cells (also known as parietal cells). These cells contain abundant carbonic anhydrase, and secrete hydrochloric acid. They are also thought to secrete intrinsic factor, which is necessary for the absorption of vitamin B12 in the terminal ileum. They do NOT secrete or absorb vitamin B12.

Question 85

This is part of the wall of the stomach. Which statement regarding the cells indicated by blue arrows is TRUE? 1. These are cuboidal cells 2. They are found at the pylorus 3. They secrete amylase 4. They secrete hydrochloric acid 5. Their secretions play a role in protein digestion

Answer 85

5. Their secretions play a role in protein digestion. These are gastric chief cells, which lie deep in the gastric glands, close to the muscularis mucosa. They are pyramidal cells which secrete pepsinogen (which is converted to the active protease pepsin) and lipases. Amylase is not produced in the stomach. Hydrochloric acid is secreted by the parietal (oxyntic) cells.

Question 86

This is a lower-magnification view of part of the intestines. Which statement is TRUE? 1. Lymphocytes are not present amongst the epithelial cells 2. Stem cells are located on the tips of the villi 3. This is duodenum 4. The tissue contains glands which neutralise alkaline bile 5. The villi are shorter than the crypts

Answer 86

3. This is duodenum. This is, and can only be duodenum. Why? Because it comprises a mucosa with a villous architecture and a submucosa containing Brunner's glands. Brunner's glands are NOT found in the jejunum and ileum (allowing you to distinguish between duodenum and the other parts of the small intestine). It is worth noting that in clinical pathological practice a biopsy taken from the duodenum which does not include Brunner's glands can only be described as coming from the small intestine. Brunner's glands produce an alkaline secretion which helps neutralise acidic chyme from the stomach. Duodenal epithelium does normally contain a small number of intra-epithelial lymphocytes and normally has long villi and short crypts. Increased numbers of intra-epithelial lymphocytes, villous atrophy and crypt hypertrophy are features of gluten-sensitive enteropathy (coeliac disease). The stem cells are located at the base of the crypts (as occurs elsewhere in the intestines)

Question 87

Which statement concerning this tissue, shown at low magnification, is TRUE? 1. It has a well-developed muscularis mucosa 2. It receives its blood supply from a branch of the superior mesenteric artery 3. Lymphoid tissue is confined to the submucosa 4. The mucosa is thrown into villi 5. The submucosal lymphoid tissue becomes more prominent in old age

Answer 87

2. It receives its blood supply from a branch of the superior mesenteric artery. This is the vermiform appendix, identifiable because all of it fits onto a microscope slide, it is lined by a flat mucosa lacking villi, has abundant lymphoid tissue in the lamina propria and submucosa and lacks a muscularis mucosa. The lymphoid tissue of the appendix is most abundant in childhood and declines with increasing age. The appendix is part of the embryological mid-gut and so does indeed derive its blood supply from a branch of the superior mesenteric artery (as does the rest of the mid-gut).

Question 88

Which of the following statements concerning this part of the gut is TRUE? 1. It is the site of absorption of vitamin B12 2. It lacks a muscularis mucosa 3. Stem cells are located at the base of the crypts 4. This could be from the ascending colon, but could not be from the descending colon 5. This is normal gastric antrum

Answer 88

3. Stem cells are located at the base of the crypts. This is normal colonic mucosa, identified by the presence of a flat surface (no villi). There are numerous straight crypts, lined by enterocytes and abundant goblet cells, which secrete lubricating mucus. There is a prominent muscularis mucosa, and as seen in the picture the crypts reach down to touch it. As in other parts of the intestines, stem cells are located at the base of the crypts. There is no histological difference between colonic mucosa from the caecum, ascending colon, transverse colon, descending colon and sigmoid colon and it is not possible to tell these parts of the bowel apart histologically. Vitamin B12 is absorbed, with the aid of intrinsic factor, in the terminal ileum, NOT the colon. Normal gastric mucosa does not contain lymphocytes in the lamina propria - this CANNOT be normal stomach.

Question 89

Which of the following statements concerning the anus and rectum is TRUE? 1. Perianal skin lacks sebaceous glands 2. The anus is lined by the same type of epithelium as the tongue 3. The rectal mucosa is histologically similar to that of the terminal ileum 4. There are no veins in the submucosa at the anorectal junction 5. There is a gradual transition between the epithelium lining the rectum and that lining the anus

Answer 89

2. The anus is lined by the same type of epithelium as the tongue. The anus and tongue are indeed both lined by stratified squamous epithelium. The proximal anal canal and the under-surface of the tongue are non-keratinsed. The distal anal canal and upper surface of the tongue are keratinised. There is an abrupt transition from the simple columnar epithelium of the rectum to the stratified squamous epithelium of the anus. At this point, the submucosa contains a plexus of prominent veins which may dilate and give rise to haemorrhoids. Perianal skin is hair-bearing and contains modified sebaceous glands. Rectal mucosa is histologically similar to that of the colon, not the small intestine.

Question 90

Which of the following statements concerning this tissue is TRUE? 1. It is stained with haematoxylin and eosin 2. The blue-stained cells are derived from monocytes 3. The blue-stained cells are Ito cells 4. The blue-stained cells lack nuclei 5. The blue-stained cells secrete bile

Answer 90

2. The blue-stained cells are derived from monocytes. This is liver, stained with eosin (but not haematoxylin, which is why you cannot see the hepatocytes nuclei!). The cells stained blue are Kupffer cells, which have phagocytosed a blue/black dye (India ink). Kupffer cells are phagocytic are of monocyte lineage. Bile is secreted by hepatocytes.

Question 91

Which statement regarding this tissue is TRUE? 1. The hepatocytes adjacent to the curved arrow are the most poorly oxygenated in the liver 2. The structure at the top of the image marked by a large arrow is a branch of the hepatic artery 3. The structure marked by an arrow-head conveys nutrient-rich blood to the liver 4. The structure marked by the arrow-head conveys oxygenated blood to the liver 5. The structure marked by the long straight thin arrow is a branch of the portal vein

Answer 91

3. The structure marked by an arrow-head conveys nutrient-rich blood to the liver. This is a normal portal tract, containing a bile duct (thick arrow, top of image), branch of the hepatic artery (thin arrow) and branch of the portal vein (arrow-head). The portal vein conveys deoxygenated but nutrient rich blood from the intestines to the liver. The hepatocytes closest to the portal tracts are closest to the branches of the hepatic arteries, which convey oxygenated blood to the liver. These hepatocytes are therefore the most richly oxygenated in the liver.

Question 92

Which statement is TRUE? 1. The epithelial cells are adapted for the absorption of water 2. The epithelium has a villous architecture 3. The epithelial cells lack a microvillous brush border 4. The epithelial cells secrete bile 5. This is the common bile duct

Answer 92

3. The epithelial cells are adapted for the absorption of water. This is taken from the gallbladder. The epithelium is thrown into folds but not villi. The epithelial cells in the gallbladder are columnar (as seen in the picture). This cannot be bile duct, which is lined by cuboidal epithelial cells. The epithelial cells have a poorly developed, but nonetheless present, microvillous brush border and are adapted to absorb water, so concentrating bile. Bile is secreted by hepatocytes, not by biliary epithelium.

Question 93

This is pancreas. Which statement is TRUE concerning the cells marked by green arrows? 1. Cholecystokinin stimulation causes them to release an acidic secretion 2. Secretin stimulation causes them to release enzymes by exocytosis 3. They secrete bicarbonate ions 4. They secrete insulin 5. They secrete pancreatic polypeptide

Answer 93

3. They secrete bicarbonate ions. The green arrows point to centoacinar cells (of Langerhans) in the exocrine pancreas. These cells secrete a bicarbonate-rich alkaline solution when stimulated by secretin. They can also secrete mucin. Cholecystokinin causes the surrounding acinar cells (which are pyramidal cells that have abundant apical eosinophilic cytoplasm) to release digestive enzymes by exocytosis. Insulin and pancreatic polypeptide are secreted by the cells of the islets of Langerhans, which are not shown in this image.

Question 94

Which of the following statements concerning hepatocytes is TRUE? 1. Their rough endoplasmic reticulum is the site of drug inactivation 2. They are arranged in acini 3. They are pyramidal cells 4. They do not contain smooth endoplasmic reticulum 5. They usually contain glycogen particles

Answer 94

5. They usually contain glycogen particles. Hepatocytes are large polygonal cells that are arranged in plates comprising thin cords of hepatocytes, supported by a meshwork of type 3 collagen (reticulin). Their abundant smooth endoplasmic reticulum bears enzymes which inactive drugs and toxins. Their abundant rough endoplasmic reticulum plays a role in the synthesis of plasma proteins. Hepatocytes usually do contain glycogen particles.

Question 95

Which of the following statements concerning liver is TRUE? 1. 80% of the blood supply to the liver comes from the hepatic artery 2. Blood flowing through hepatic sinusoids drains into the portal veins 3. Ito cells store fat 4. Kupffer cells secrete bile 5. The liver contains a delicate meshwork of type II collagen

Answer 95

3. Ito cells store fat. Ito cells are located in the space of Disse and store fat. They play a pivotal role in fatty degeneration and fibrosis of the liver in conditions such as cirrhosis. The liver is supported by a delicate meshwork of reticulin (type III collagen). Blood flows through the hepatic sinusoids from the portal vein and hepatic artery to the central veins. Approximately 30% of the liver's blood supply comes from the hepatic artery. The rest comes from the portal vein. Kupffer cells phagocytose particulate matter including bacteria. Bile is secreted by hepatocytes.

Question 96

This is a section of kidney stained with haematoxylin and what other stain? 1. Alcian blue 2. Eosin 3. Massons 4. Periodic acid Schiff 5. Perls reaction

Answer 96

4. Periodic acid Schiff. High magnification picture of a renal glomerulus stained by the PAS procedure. Note the strong staining of the Bowman's capsule that surrounds the glomerulus and of the filtration membrane within the glomerular tuft.

Question 97

Which of the following statements about the structure in the centre of this image is TRUE? 1. It contains a basement membrane synthesised solely by Podocytes 2. It is a filter permeable to solutes up to 100,000 Daltons 3. It is a filter whose pores are guarded only by the filtration membrane 4. It is a filter with a basement membrane composed of type III collagen 5. The endothelial cells have complex foot processes

Answer 97

3. It is a filter whose are guarded only by the filtration membrane. This is a renal glomerulus, which acts as a filter to water and solutes up to 50000 Daltons. The filter is guarded only by the basement (filtration) membrane. Both the Podocytes and the endothelial cells contribute to the basement membrane. However it is the Podocytes, not the endothelial cells, which have foot processes.

Question 98

A 46-year-old man has type 1 diabetes mellitus which has resulted in renal damage. Which of the following statements concerning his Glomerular basement membranes is most likely to be TRUE? 1. They have become fenestrated 2. They will have become thickened 3. They will have become thinned 4. They will have been destroyed 5. They will have an increased filtration capability

Answer 98

2. They will have become thickened. In diabetes mellitus the basement membrane becomes thickened, due to an accumulation of additional glucose residues within it. This reduces its filtration capability.

Question 99

Which of the following statements concerning this image is TRUE? 1. Antidiuretic hormone acts on the structures lined by columnar epithelium 2. This is an admixture of proximal and distal convoluted tubules 3. This is part of the renal cortex 4. The structures lined by a flat epithelium are all impermeable to water 5. The structures lined by columnar epithelium are ultrastructurally similar to the convoluted tubules

Answer 99

5. The structures lines by columnar epithelium are ultrastrucurally similar to the convoluted tubules. This is renal medulla, showing an admixture of thick and thin limbs of the loops of Henle. Those tubules lined by columnar epithelium are thick limbs of the loops of Henle, and these are structurally similar to the proximal and distal convoluted tubules. Those tubules lined by flat epithelium are the thin limbs of the loops of Henle. While ascending limbs are impermeable to water (unless acted upon by ADH), the descending thin limbs are highly water permeable. You cant distinguish the ascending from the descending thin limbs however on H+E.

Question 100

Which of the following statements regarding diabetes insipidus is TRUE? 1. It is due to an excess of ADH 2. The patient will complain of severe thirst 3. The urine contains more calcium than normal 4. The urine contains more glucose than normal 5. The urine is more concentrated than normal

Answer 100

2. The patient will complain of severe thrist. Diabetes insipidus is the result of an absence of ADH. This prevents the distal tubule and collecting ducts from resorbing water and concentrating the urine. As a consequence patients produce large quantities of dilute urine and suffer from extreme thirst. The urine of patients with diabetes mellitus contains more glucose than normal. (These diseases were so named because of the taste of the patient's urine. Be glad that modern laboratory medicine has become more advanced!)

Question 101

Which of the following parts of the kidney is particularly responsive to aldosterone? 1. Collecting ducts 2. Glomerulus 3. Juxta-Glomerular apparatus 4. Lacis cells 5. Proximal convoluted tubules

Answer 101

1. Collecting ducts. Cells of the distal tubule and collecting ducts are the most sensitive to Aldosterone. This is where this hormone promotes the reabsoption of sodium ions and water and thereby concentrates the urine and conserves body fluid.

Question 102

Which of the following structures is NOT lined by this type of epithelium 1. Bladder 2. Prostatic urethra 3. Renal pelvis 4. Ureter 5. Urethral meatus

Answer 102

5. Urethral meatus. With the exception of the urethral meatus (which is lined by stratified squamous epithelium) all of these structures are lined by urothelium (which is what is shown in the image).

Question 103

Which of the following statements concerning the urethra is TRUE? 1. Mucous glands are found along its length 2. The female urethra is longer than the male urethra 3. The female urethra is divided into four distinct anatomical parts 4. The male urethra is predominantly lined by stratified squamous epithelium 5. The proximal end of the urethra is lined by simple columnar epithelium

Answer 103

1. Mucous glands are found along its length. The urethra is longer in the male than in the female and is divisible into prostatic, membranous, bulbous and pendulous parts. It is lined mainly by a pseudo-stratified columnar epithelium (urothelium) except at its distal (penile) end. Mucous glands are found along its whole length. In the female the urethra is lined by a stratified squamous epithelium punctuated by areas of mucous glands. In both sexes a striated (voluntary) muscle sphincter derived from the muscles of the pelvic diaphragm surround the membranous part of the urethra.

Question 104

Which of the following glands drain into the penile urethra? 1. Bartholins glands 2. Cowpers glands 3. Prostate 4. Seminal vesicles 5. Skenes glands

Answer 104

2. Cowpers glands. The Cowper's (or Bulbo-urethral) glands drain into the penile urethra. The prostate and seminal vesicles drain into the prostatic urethra. Skene's glands are the female equivalent of the prostate. Bartholin's glands secrete mucus to lubricate the vagina.

Question 105

This is a section of which part of the male reproductive tract? 1. Efferent ductules 2. Epididymis 3. Rete testis 4. Seminiferous tubule 5. Urethra

Answer 105

2. Epididymis. This is a section through the epididymis which is lined by a pseudo-stratified columnar epithelium. The cells at the surface bear long "stereocilia" that protrude into its lumen. Note also the aggregates of spermatozoa in the lumen.

Question 106

Which of the following statements about the testis is TRUE? 1. Leydig cells form the blood:testis barrier 2. Leydig cells nurture the developing gametes 3. Sertoli cells have a phagocytic function 4. Sertoli cells lie in the interstitium between the seminiferous tubules 5. Sertoli cells secrete testosterone

Answer 106

3. Sertoli cells have a phagocytic function. Sertoli cells line the seminiferous tubules. They nuture the developing Spermatogonia and phagocytose the cellular detritus shed by the gametes as they mature. They also form the blood:testis barrier. Leydig cells lie in the interstitium between the seminiferous tubules and secrete testosterone.

Question 107

This is which part of the male reproductive tract? 1. Epididymis 2. Penile urethra 3. Rete testis 4. Seminferous tubule 5. Vas deferens

Answer 107

5. Vas deferens. This is vas deferens in transverse section. Although the epithelium is similar to that of the epididymis the muscle coat is much much thicker.

Question 108

Which of the following statements concerning this structure is TRUE? 1. Hypertrophy of the epithelial cells causes it to enlarge with age 2. It has a well-defined fibrous capsule 3. Lipofuschin is commonly found within the epithelial cells 4. It contains skeletal muscle 5. It produces a secretion containing acid phosphatse

Answer 108

5. It produces a secretion containing acid phosphatase. This is prostate. The prostate lacks a well-defined fibrous capsule and contains smooth rather than skeletal muscle. The prostate does commonly enlarge with age - but as a result of epithelial and stromal hyperplasia (NOT hypertrophy). Lipofuschin may be found in the epithelial cells of the seminal vesicles but it isn't seen in the prostate. Prostatic secretions contain acid phosphatase.

Question 109

This is a section of which part of the male reproductive tract? 1. Membranous urethra 2. Penile urethra 3. Prostatic urethra 4. Seminferous tubule 5. Vas deferens

Answer 109

2. Penile urethra. This is a picture of the lining of the penile urethra showing a pseudostratified epithelium with underlying loose connective tissue.

Question 110

This is which part of the male reproductive tract? 1. Corpus cavernosum 2. Corpus spongiosum 3. Prostate 4. Rete testis 5. Seminal vesicle

Answer 110

2. Corpus spongiosum. This is the corpus spongiosum of the penis, comprising loose connective tissue, numerous vascular channels and the penile urethra.

Question 111

What are these? 1. Atritic follicles 2. Graafian follicles 3. Leydig cells 4. Primary oocytes 5. Primordial follicles

Answer 111

5. Primordial follicles. This is part of the cortex of an ovary (sheep) showing primordial germ cells surrounded by fibroblast-like stromal cells. The surface of the ovary (germinal epithelium) is at the top of the picture.

Question 112

Which hormone is secreted by this structure? 1. Human chorionic gonadotrophin 2. Luteinising hormone 3. Progesterone 4. Prolactin 5. Testosterone

Answer 112

3. Progesterone. This is a high magnification picture of part of a corpus luteum showing cells of the theca interna and blood vessels running between them. It produces progesterone although a small proportion of the cells, often found at the centre of the corpus, continue to synthesize oestrogen. The cells are known as thecal lutein cells

Question 113

Which of the following statements is TRUE? 1. Ectopic pregnancy at this site is very rare 2. This epithelium does not contain mucus-secreting cells 3. This epithelium is not hormonally sensitive 4. This epithelium secretes mucus as a barrier to sperm 5. This is usual site of fertilisation

Answer 113

5. This is usual site of fertilisation. This is fallopian tube epithelium. All parts of the female reproductive tract are hormonally sensitive. The fallopian tube is both the commonest site for fertilisation and the commonest site of ectopic pregnancy. The epithelium produces mucus that is wafted by cilia to aid the passage of sperm and ovum.

Question 114

Which of the following would you NOT expect to find within this tissue? 1. Decidualised stromal cells 2. Luminal secretions 3. Mitotic figures 4. Spiral arteries 5. Tortuous glands

Answer 114

3. Mitotic figures. This is secretory endometrium (late secretory phase), comprising tortuous glands containing secretions, spiral arteries and condensations of decidualised stroma around the arteries. You would not expect to find mitotic figures, as they are found in proliferative endometrium (when indeed, all of the other options are the absent).

Question 115

This is endometrium taken during which phase of the menstrual cycle? 1. Proliferative 2. Early secretory 3. Late secretory 4. Mid-secretory 5. Menstrual

Answer 115

3. Late secretory. This is late secretory phase endometrium, comprising tortuous glands containing secretions, spiral arteries and condensations of decidualised stroma around the arteries. There is also some stromal oedema. In proliferative endometrium the glands are straight, contain mitotic figures, and lack secretions and the stroma lacks decidualisation. Spiral arteries are not seen in proliferative endometrium. In early secretory endometrium you would see vacuoles within the epithelial cells. In mid-secretory endometrium you would not expect to see the condensation of stroma around the spiral arteries.

Question 116

This is part of the uterus. Which statement is FALSE? 1. It contains vessels that give rise to the spiral arteries of the endometrium 2. It is an uncommon site for neoplasia 3. It is hormonally sensitive 4. It undergoes hyperplasia during pregnancy 5. This is smooth muscle

Answer 116

2. It is an uncommon site for neoplasia. This is myometrium - the smooth muscle wall of the uterus. The myometrium is hormonally sensitive and enlarges during pregnancy due to hyperplasia and hypertrophy to accommodate the growing fetus. The myometrium is the commonest site in the female genital tract for benign neoplasia. Benign neoplasms of this tissue (leiomyomas/fibroids) are very common indeed.

Question 117

Which of the following statements regarding this tissue is TRUE? 1. It rarely undergoes malignant transformation 2. Malignant tumours at this site are usually adenocarcinomas 3. The precise location of this varies with age 4. This is a vaginal ulcer 5. This tissue is not hormonally active

Answer 117

3. The precise location of this varies with age. This is the cervical transformation zone (the junction between the ectocervix (on the left) and the endocervix (on the right). The position of this junction on the cervix changes with age, dependent on hormonal stimulation. The cervical transformation zone is the commonest part of the cervix to be affected by malignant transformation, but most of the cancers at this site are squamous cell carcinomas. This isn't the vagina (and cannot be), and there is no ulcer here! (An ulcer is a breach in an epithelial surface, and the epithelium is intact)

Question 118

Which of the following statements is TRUE? 1. The cells with dark blue cytoplasm secrete growth hormone 2. The cells with eosinophilic cytoplasm do not secrete hormones 3. The cells with eosinophilic cytoplasm secrete prolactin 4. The cells with pale blue cytoplasm are basophils 5. This is part of the posterior pituitary gland

Answer 118

3. The cells with eosinophilic cytoplasm secrete prolactin. This is part of the anterior pituitary gland which contains acidophils (eosinophilic cytoplasm, secrete growth hormone and prolactin), basophils (dark blue cytoplasm, corticotrophs, thyrotrophs and gonadotrophs) and chromophobes (pale blue cytoplasm, probably non-secretory).

Question 119

Which statement about this tissue is TRUE? 1. These cells are of neuronal origin 2. These cells produce steroid-based hormones 3. These cells receive their blood supply via a portal circulation 4. The release of hormones by this tissue is regulated by factors produced in the pineal gland 5. The vascular supply to these cells originates in the posterior pituitary gland

Answer 119

3. These cells receive their blood supply via a portal circulation. This is anterior pituitary, which produces peptide-based hormones. The anterior pituitary receives its blood supply from a portal circulation which starts in the hypothalamus. This part of the gland is of epithelial origin

Question 120

Which of the following statements is TRUE? 1. The gland was metabolically inactive when this sample was taken 2. The pink material is rich in thyroxine 3. The pink material is predominantly converted into tri-iodothyronine 4. This is parathyroid tissue 5. This tissue arose from the floor of the mouth in embryonic life

Answer 120

5. This tissue arose from the floor of the mouth in embryonic life. This is thyroid tissue. The thyroid originates from the floor of the mouth. The epithelial cells produce thyroxine, predominantly as tetra-iodothyronine, from thyroglobulin which is stored as the pink-staining material colloid. When metabolically active, as in this picture, the epithelial cells take on a columnar appearance (when inactive they are flattened and cuboidal).

Question 121

Which statement concerning the cell highlighted by the red arrow is TRUE? 1. It secretes calcitonin 2. It secretes parathyroid hormone 3. It secretes thyroxine 4. It secretes vitamin D 5. It will secrete a hormone if the blood calcium concentration falls

Answer 121

1. It secretes calcitonin. This is a parafollicular C-cell and these produce calcitonin when the blood calcium concentration rises. It is antagonistic to parathyroid hormone.

Question 122

Which statement concerning the cells in the centre of the image is TRUE? 1. 20% of them secrete calcitonin 2. 20% of them secrete glucagon 3. 20% of them secrete pancreatic polypeptide 4. 20% of them secrete insulin 5. 50% of them secrete somatostatin

Answer 122

2. 20% of them secrete glucagon. This is an Islet of Langerhans, the endocrine component of the pancreas. 70% of the islet is composed of beta cells secreting insulin, 20% are alpha cells secreting glucagon, 8% are delta cells secreting somatostatin and 2% are cells secreting pancreatic polypeptide.

Question 123

Which of these statements concerning the pancreatic Islets of Langerhans is TRUE? 1. Alpha and beta cells can be readily distinguished from each other on H+E stained sections 2. The alpha cells secrete a hormone which causes hepatocytes to store glucose 3. The beta cells are predominantly found in the centre of the Islets 4. The Islets secrete their products into the duodenum 5. The secretions of the Islets pass into the hepatic portal circulation

Answer 123

5. The secretions of the islets pass into the hepatic portal circulation. The islets secrete hormones into the hepatic portal circulation (the exocrine pancreas secretes into the duodenum). Alpha cells produce glucagon, which causes hepatocytes to release glucose. Beta cells, which produce insulin, are found typically around the edge of the Islets but it isn?t possible to distinguish the cell types reliably on H+E section.

Question 124

Which of the following statements regarding this part of the adrenal gland is TRUE? 1. The layer of cells at the top of this image secretes sex-steroids 2. The lowermost layer secretes cortisol 3. The middle layer secretes aldosterone 4. This tissue secretes adrenaline and noradrenaline 5. This tissue synthesises hormones from cholesterol

Answer 124

5. This tissue synthesises hormones from cholesterol. This is the adrenal cortex. The uppermost layer (zona glomerulosa) secretes Aldosterone and other mineralocorticoids. The middle layer (zona fasciculata) secretes cortisol and other glucocorticoids. The innermost layer (zone reticulosa) secretes sex steroid hormones. The adrenal cortex uses cholesterol to synthesize hormones (hence its yellow appearance macroscopically). Adrenalin and noradrenalin are secreted by the adrenal medulla.

Question 125

Which statement regarding this part of the adrenal gland is TRUE? 1. If this tissue becomes neoplastic it can result in severe hypertension 2. It is bathed in blood that drained from the rest of the gland 3. It is predominantly innervated by the parasympathetic nervous system 4. It receives its blood supply from a large central artery 5. These cells secrete cortisol

Answer 125

1. If this tissue becomes neoplastic it can result in severe hypertension. This is adrenal medulla. The medulla secretes adrenalin and noradrenalin. The cells are bathed in blood that has drained from the cortex, which passes into a large central vein. The gland is supplied predominantly by the sympathetic nervous system, so stress will cause hormone release. Neoplasms at this site are called phaeochromocytomas and can present with severe hypertension.

Question 126

Which of the following does NOT derive directly from the primitive gut tube? 1. Adrenal gland 2. Anterior pituitary gland 3. Islets of Langerhans 4. Parathyroid glands 5. Thyroid gland

Answer 126

1. Adrenal glands. All of the above endocrine tissues arise from the primitive gut tube, with the exception of the adrenal gland.

Question 127

From which site has this skin most likely been taken? 1. Abdominal wall 2. Axilla 3. Back of the hand 4. Sole 5. Wrist

Answer 127

4. Sole. This is a picture of the epidermis of non-hairy skin. Note the dark blue staining epidermis with a thick layer of pink-staining dead squames (keratized layer) above. Note also the thin dark blue staining granular layer just below the keratinized squames. Part of the dermis is shown in the lower right hand part of the picture (pale staining). Given the thickness of the keratinized layer this is most likely to have come from the sole of the foot or the palm of the hand.

Question 128

Which statement about melanocytes is TRUE? 1. Melanocytes are derived from the embryonal mesenchyme 2. Melanocytes are more abundant in heavily pigmented skin than in fair skin 3. Melanocytes are normally present in all layers of the epidermis 4. Melanocytes are normally found in the dermis 5. Melanocytes transfer melanin to keratinocytes

Answer 128

5. Melanocytes transfer melanin to keratinocytes. Melanocytes are derived from the neural crest in embryonal life and migrate into the basal layer of the epidermis. In normal skin they should only be present in the basal layer and not in the dermis. (Melanocytes present in all layers of the epidermis is one of the features of malignant melanoma). People with heavily pigmented skin have the same number of melanocytes as those with pale skin, but in the former the melanocytes produce more melanin. Melanocytes package melanin into cytoplasmic organelles called melanosomes, and then transfer these to surrounding keratinocytes.

Question 129

Which of the following cell types is NOT found in normal epidermis? 1. Fibroblasts 2. Keratinocytes 3. Langerhan's cells 4. Melanocytes 5. Merkel cells

Answer 129

1. Fibroblasts. Most of the cells in the epidermis are keratinocytes. Admixed, but often difficult to see on H+E sections, are Merkel cells and Langerhan's cells. Merkel cells are predominantly found in the basal layer and form synapses with nerve fibres in the dermis. They provide us with a sensation of fine touch. Langerhan's cells are typically located within the stratum spinosum and are part of the immune system. Melanocytes are present in the basal layer of the epidermis. Fibroblasts are found in the dermis but not in the epidermis.

Question 130

Which statement concerning hair-bearing skin is TRUE? 1. Hairs are formed from the secretions of sebaceous glands 2. Hairs are pigmented by the secretions of sebaceous glands 3. Parasympathetic stimulation causes contraction of the erector pili muscles 4. The root sheath has a thinned basement membrane 5. The root sheath is a downwards projection of epidermis

Answer 130

5. The root sheath is a downwards projection of epidermis. Hair follicles are epidermal adnexal structures and arise as downward projections of the epidermis into the dermis. They are lined by the same layers of cells as seen elsewhere in the epidermis, but the basement membrane is thickened (Glassy membrane). The secretions of sebaceous glands lubricate the hair, but the hair itself is pigmented by melanocytes in the germinative epithelium and is composed of keratin. Sympathetic stimulation causes contraction of the erector pili muscles.

Question 131

This is a structure found within the dermis. Which statement concerning this structure is TRUE? 1. It is a collection of arterioles 2. It is an apocrine sweat gland 3. It is an eccrine sweat gland 4. It is a Meissner's corpuscle 5. It is a Pacinian corpuscle

Answer 131

3. It is an eccrine sweat gland. This is an eccrine sweat gland. These are tightly coiled sweat glands found within the dermis that discharge a watery secretion onto the surface of the skin via a duct that is lined by simple columnar epithelium. Surrounding the secretory portion of the duct shown in the picture are myoepithelial cells which can contract to help expel the sweat.

Question 132

Which of these statements concerning sweat glands is TRUE? 1. Eccrine sweat glands are composed of three layers of cells 2. Eccrine sweat glands are lined by glycogen-rich cells 3. Eccrine sweat glands are not present in the axillae 4. Eccrine sweat glands are rare on the forehead 5. Eccrine sweat glands form in the 4th week of intrauterine life

Answer 132

2. Eccrine sweat glands are lined by glycogen-rich cells. Eccrine sweat glands appear in the skin in the 16th week of intrauterine life. These glands are tightly coiled and lined by two layers of cells - an inner glycogen-rich secretory layer and an outer indistinct contractile layer of myoepithelial cells. They are abundant on the forehead, palms, soles, axillae and scalp.

Question 133

Which of these statements concerning sweat glands is TRUE? 1. Apocrine sweat glands are lined by a deeply basophilic epithelium 2. Apocrine sweat glands are responsible for the production of ear wax 3. Apocrine sweat glands are well developed in childhood but become less prominent after puberty 4. Apocrine sweat glands have a secretion that plays a role in human sexual attraction 5. Apocrine sweat glands have ducts lined by a single layer of cells

Answer 133

2. Apocrine sweat glands are responsible for the production of ear wax. Apocrine sweat glands have an unknown function in humans, though in other animals their secretions play in role in the marking of territory and in sexual attraction. They are abundant in the axillae, groins and around the perineum. They are less numerous than eccrine glands (but their ducts are similar and lined by 2 layers of cells). The secretory portion of the gland comprises deeply eosinophilic epithelium. The ceruminous glands are modified apocrine sweat glands and produce ear wax.

Question 134

Which statement regarding sensory nerve endings in the skin TRUE? 1. Free nerve endings exist which detect pain and temperature 2. Meissner's corpuscles are located in the subcutaneous fat 3. Meissner's corpusles detect pressure 4. Merkel cells detect itch 5. Pacinian corpuscles are located at the dermo-epidermal junction

Answer 134

1. Free nerve endings exist which detect pain and temperature. Detection of cutaneous sensation is by variably specialized nerve endings. Free nerve endings (which may be myelinated or unmyelinated) detect pain, temperature and itch. Meissner's corpuscles, located in the superficial dermis in the dermal papillae are structured nerve endings which detect touch. They are most abundant in the skin of the feet and hands. Pacinian corpuscles are located in the deep dermis or subcutaneous fat and detect pressure. Merkel cells are slowly adapting touch receptors in the basal epidermis.

Question 135

Identify this tissue. 1. Apocrine sweat glands 2. Breast lobules 3. Eccrine sweat glands 4. Lactating breast tissue 5. Secretory endometrium

Answer 135

4. Lactating breast tissue. This is a picture of glandular tissue from a lactating breast. The lumena of the alveoli contain milk residue and some of the cells show pale vacuoles that in life would have contained milk fat. Part of the fibrous stroma of the breast can be seen in the bottom left hand corner.

Question 136

What has this section of skeletal muscle been stained to demonstrate? 1. Mitochondria 2. Striations 3. Type 1 fibres 4. Type 2a fibres 5. Type 2b fibres

Answer 136

2. Striations. This is a picture of skeletal muscle fibres cut in longitudinal section and stained with iron haematoxylin. The banding of the fibres (striations) can be seen. Note too the muscle cell nuclei and the row of dark stained erythrocytes within a capillary towards the bottom of the picture.

Question 137

Which of the following statements about Type 1 muscle fibres is TRUE? 1. They are fast twitch fibres 2. They are the predominant fibre type in the small muscles of the hand 3. They contain lipid droplets between the myofibrils 4. They derive most of their energy from glycolysis 5. They fatigue easily

Answer 137

3. They contain lipid droplets between the myofibrils. Type 1: Slow twitch muscle fibres are found in highest numbers in postural muscles. The fibres contain large mitochondria that lie in rows between the myofibrils. Alongside them are fat droplets that the mitochondria use as a source of triglyceride for the production of ATP. Type 1: Slow twitch muscle fibres are oxidative in terms of energy supply, are fatigue resistant and are found in highest numbers in postural muscles.

Question 138

Which of the following statements about Type 2A muscle fibres is TRUE? 1. They are fast twitch fibres 2. They are the predominant fibre type in the muscles of the back 3. They contain numerous large mitochondria 4. They derive their energy solely from glycolysis 5. They fatigue easily

Answer 138

1. They are fast twitch fibres. Type 2A: Fast twitch muscle fibres use a mixture of both oxidative & glycolytic processes to obtain their energy and are moderately fatigue resistant. Compared with slow twitch muscles these fibres have fewer and smaller mitochondria but contain large reserves of carbohydrate in the form of glycogen that they utilise in the production of ATP.

Question 139

Which of the following statements concerning sarcomeres is TRUE? 1. During contraction, fibres from the I band slide between the fibres in the A band 2. Myosin filaments are attached to the Z-lines 3. Myosin filaments form the A band of the sarcomere 4. Sarcomeres can shorten to 50% of their resting length 5. Titin is the thin contractile sarcomeric filament

Answer 139

1. During contraction, fibres from the I band slide between the fibres in the A band. The two major contractile proteins are myosin that forms the bipolar thick filaments and actin that forms the thin filaments that interdigitate with the myosin filaments and are attached to the Z lines. Together these filaments are responsible for the contraction of skeletal muscle. When stimulated, the thin actin filaments may slide deeper within the A band (from both ends) bringing the Z lines closer together and shortening the sarcomere (extrinsic work). The maximum amount of shortening of a sarcomere is 30%. Alternatively shortening is minimal but tension within the muscle increases (intrinsic work). A number of other important structural non-contractile proteins are contained within a sarcomere one of which, titin, is illustrated alongside. These play an important part in maintaining the structural integrity of the myofibrils.

Question 140

This is muscle which has been stained to demonstrate the presence of fibrillar ATPase. Which of the following statements regarding this muscle is TRUE? 1. The darkly staining cells are Type 2A fibres 2. The darkly staining cells contain numerous mitochondria 3. The darkly staining cells fatigue easily 4. The pale-staining cells are pale because their cytoplasm contains abundant lipid 5. The pale-staining cells are abundant in the postural muscles

Answer 140

2. The darkly staining cells contain numerous mitochondria. This picture illustrates slow and fast fibre types cut in transverse section, (taken from Human Histology, Stevens & Lowe, 3 edition page 245). The tissue has been stained to demonstrate the presence of fibrillar ATPase that is present (dark brown staining) in larger amounts in Type 1, slow twitch muscles that have greater numbers of mitochondria and are oxidative in nature. Lipid droplets are present between the myofibrils but this cannot be seen by light microscopy. The pale staining Type 2 fibres have fewer mitochondria (and less fibrillar ATPase) and depend on glycolytic processes for their energy. Consequently the pale-staining cells contain abundant glycogen between the myofibrils.

Question 141

Which type of collagen is this structure made of? 1. Type 1 2. Type 2 3. Type 3 4. Type 4 5. Type 5

Answer 141

1. Type 1. This is a picture of a Sharpey fibre connecting muscle fibres (oblique above) to the periosteum of bone (below). Dense pink staining bone appears at the bottom of the picture while the periosteum above it has two layers, a lower pale-staining cellular layer and an upper fibrous layer with which the Sharpey fibre merges. Like tendons, Sharpey fibres are composed of Type 1 collagen.

Question 142

Which cell type can be seen in this picture? 1. Chondroblast 2. Fibroblast 3. Myofibroblast 4. Skeletal myocyte 5. Smooth muscle myocyte

Answer 142

2. Fibroblast. This is a picture of part of a tendon stained with H&E. Note the pink staining collagen bundles with fibroblasts (with blue staining nuclei) sandwiched between them. (Striated muscle cells have striated cytoplasm. Smooth muscle myocytes have central nuclei.)

Question 143

Which statement concerning this image is FALSE? 1. These structures are abundant in muscles involved with fine movements 2. This is a muscle spindle 3. This is a sensory organ 4. This senses the amount of tension within the surrounding muscle

Answer 143

4. This senses the amount of tension within the surrounding muscle. his specimen was taken from an intrinsic muscle of the hand close to its insertion into a bone. Muscle spindles are sensory organs embedded within muscles. They consist of a small number of muscle fibres (intrafusal fibres) isolated from the surrounding muscle (extrafusal fibres) by a connective tissue sheath. The intrafusal fibres have nerve fibres wound around them. They are arranged in parallel with the main (extrafusal) muscle fibres and relay information concerning the degree of contraction of the surrounding muscle. The number of spindles within a muscle varies considerably. Muscles involved with fine movements with small motor units have more spindles than those muscles with larger motor units concerned with course movements.

Question 144

This is part of the template that will form a bone in an 8-year-old child. Which statement is TRUE? 1. The entrapped cells are osteocytes 2. This could be part of the template that forms the vault of the skull 3. This is demineralised bone 4. This is fibrous cartilage 5, This is from the epiphyseal growth plate

Answer 144

5. This is from the epiphyseal growth plate. This is a picture of hyaline cartilage taken from the head of a growing long bone. Note the amorphous matrix and the dark-staining chondrocytes traped within it. The vault of the skull is formed by intramembranous ossification.

Question 145

This is part of a bone developing by intramembranous ossification. What are the cells that are lining the developing bone? 1. Chondroblasts 2. Chondrocytes 3. Fibroblasts 4. Osteoblasts 5. Osteocytes

Answer 145

4. Osteoblasts. This is a picture showing part of developing membrane bone growing in a primitive mesenchyme (blue stained) taken from from the vault of a skull. Rows of osteoblasts can be seen lining the holes of this loose meshwork of immature bone. Osteocytes are multinucleate cells of macrophage lineage.

Question 146

Which of the statements concerning the cells lined in rows on this developing bone is TRUE? 1. They are metabolically inactive 2. They are remodelling the bone 3. They are resorbing bone 4. They are secreting type 4 collagen 5. They are synthesising osteoid

Answer 146

5. They are synthesising osteoid. These are osteoblasts, which lay down an unmineralised connective tissue (osteoid) rich in type 1 collagen, that will become mineralized to form bone. Osteoclasts resorb/remodel bone.

Question 147

What does this image show? 1. An osteon 2. A Volkman canal 3. Cancellous bone 4. Demineralised bone 5. An osteocyte

Answer 147

1. An osteon. This is apicture showing part of a slither of unstained native long bone showing an osteon sectioned transversely. At the centre is a golden-coloured Haversian canal the carries blood vessels, nerves and lymphatic deep into the bone.

Question 148

This is part of a bone that has been demineralised, sectioned and stained with H+E. Which statement concerning the tissue at the top of the image is TRUE? 1. Cells in the uppermost (outer) layer secrete osteoid 2. The uppermost (outer) layer contains osteoblasts 3. The thin pale-staining (inner) layer contains osteoprogenitor cells 4. This tissue is insensitive to pain 5. This tissue is richly vascular

Answer 148

3. The thin pale-staining (inner) layer contains osteoprogenitor cells. This is a picture showing part of a decalcified long bone (sectioned longitudinally) stained with H&E showing secondary compact bone with its periosteum above. The uppermost layer is fibrous and contains fibroblasts. The inner osteogenic (or cambium) layer contains osteoblasts and osteoprogenitor cells. A row of dark blue staining osteoblasts can be seen on a thin pinker layer of osteoid on the surface of the bone. Periosteum is richly innervated and exquisitively sensitive to pain.