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Question 1
Incorrect
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What is the name of the cells that make up the outermost layer of the retina and are first exposed to light?
Your Answer: Photoreceptors
Correct Answer: Ganglion cells
Explanation:The Retina and its Cell Types
The retina is composed of various types of cells, with the ganglion cell layer being the most superficial layer that is first exposed to light. Ganglion cells are the only neurons present in the retina, and they have an axon that extends centrally to form the optic nerve. These cells form synapses with bipolar cells, which are located deeper in the retina. Bipolar cells, in turn, synapse with photoreceptors, which are situated in the deepest layer of the retina. Supporting cells such as horizontal cells and amacrine cells are positioned between the other cells.
Photoreceptors play a crucial role in the retina by absorbing light and generating electrical impulses that travel through the optic nerve to the occipital lobe, where photographic images are created. The retina’s complex structure and the interactions between its various cell types enable us to see the world around us.
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This question is part of the following fields:
- Histology
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Question 2
Incorrect
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In what location can calcitonin-secreting C-cells be found?
Your Answer: In the parathyroid gland
Correct Answer: Between thyroid follicles
Explanation:Endocrine Glands and Cells in the Body
The thyroid gland is composed of follicles that contain colloid and are lined by follicular cells. These cells produce thyroid hormones, T4 and T3. The parafollicular cells, also known as C-cells, are located between the thyroid follicles and produce calcitonin. Calcitonin is produced in hypercalcaemia and inhibits osteoclast resorption of bone, which promotes hypocalcaemia. Tumours of the parafollicular cells can cause hypocalcaemia and have raised levels of calcitonin.
The parathyroid gland produces parathyroid hormone, which activates osteoclasts and promotes hypercalcaemia. This hormone works in conjunction with vitamin D. The islets of Langerhans contain alpha-cells, beta-cells, and delta-cells. These cells produce glucagon, insulin, and somatostatin, respectively. Lastly, there are multiple endocrine cells in the duodenal mucosa that secrete hormones with various gastrointestinal and metabolic functions. These cells include S-cells, L-cells, and I-cells.
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This question is part of the following fields:
- Histology
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Question 3
Correct
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Which types of cells have cilia that are capable of movement?
Your Answer: Fallopian tube epithelial cells
Explanation:Cilia, Flagella, and Microvilli: Cellular Projections with Unique Functions
Cilia, flagella, and microvilli are cellular projections that serve different functions in various cells. Cilia are hair-like structures made up of microtubules and dynein proteins. They can be either immotile or motile, with immotile cilia used for sensory transduction and attachment to underlying tissues, while motile cilia beat rhythmically to move fluid over the surface of cells or confer motility to cells. Cilia are found in the respiratory tract and Fallopian tube epithelium.
Flagella, on the other hand, are longer projections that are classified as a type of cilium. Spermatozoa have a long flagellum that has a similar internal structure to a cilium but is much longer and is used for motility.
Microvilli are folds of the cell membrane that increase the surface area for absorption. They are found in cells such as ileal enterocytes, which are responsible for nutrient absorption in the small intestine.
In summary, cilia, flagella, and microvilli are cellular projections that serve unique functions in different cells. While cilia can be either immotile or motile, flagella are longer and used for motility, and microvilli increase surface area for absorption.
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This question is part of the following fields:
- Histology
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Question 4
Incorrect
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What characteristic might indicate the presence of high-grade dysplasia?
Your Answer: Few nucleoli
Correct Answer: High Ki67 index
Explanation:Dysplasia and its Association with Malignancy
Dysplasia refers to the cellular changes that occur during the development of malignancy. The degree of dysplasia in a cell is directly proportional to its likelihood of being found in an invasive cancer. Cells with higher-grade dysplasia have more genetic abnormalities than those with low-grade dysplasia.
Progressive dysplasia is characterized by variations in the appearance of cells and their nuclei, which is not typical in most tissues where cells appear similar. The nuclei of dysplastic cells are larger, and there is an increase in the number of nucleoli. The Ki67 index is a marker of proliferation, and a higher Ki67 index indicates a higher rate of cell turnover.
In most tissues, mitoses are rare, but malignant tissues made up of dysplastic cells show visible mitoses. dysplasia and its association with malignancy is crucial in the early detection and treatment of cancer.
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This question is part of the following fields:
- Histology
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Question 5
Incorrect
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What is the epithelial lining of the ectocervix?
Your Answer: Pseudostraitified columnar
Correct Answer: Stratified squamous
Explanation:The human body is composed of approximately 50-60% total body water, with men having a higher percentage of water at around 60%. This means that a 70Kg man would have approximately 42 litres of total body water.
This water is divided into two main categories: extracellular fluid and intracellular fluid. Extracellular fluid makes up one third of the total body water and is further divided into four subcategories: plasma, interstitial fluid, lymph, and transcellular fluid.
Plasma makes up 3.5 litres, interstitial fluid makes up 8.5 litres, while lymph and transcellular fluid each make up 1.5 litres. The remaining two thirds of the total body water is intracellular fluid.
It is important to note that the concentration of electrolytes, such as potassium, in the extracellular fluid is crucial for maintaining proper bodily function. In fact, an extracellular fluid concentration of 12 mmol/L of potassium is incompatible with life.
The body’s fluid composition is essential for maintaining overall health and wellness.
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This question is part of the following fields:
- Histology
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Question 6
Correct
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Which type of cell creates the visceral peritoneum?
Your Answer: Mesothelial cells
Explanation:Different Types of Cells in the Body
Mesothelial cells are a type of flat epithelial cells that are responsible for lining cavities in the body. These cells can be found in the parietal and visceral pleura, peritoneum, tunica vaginalis, and pericardium. They secrete a small amount of lubricant fluid that allows the parietal and visceral layers to move against each other with low friction. However, mesothelial cells are also known for their development into mesothelioma, a malignant tumor that is strongly associated with asbestos exposure and has a poor prognosis.
Endothelial cells, on the other hand, are responsible for lining blood vessels. Fibroblasts are cells that secrete extracellular matrix, which is important for tissue repair and wound healing. Mesangial cells are supporting cells of the glomerular capillaries, which are responsible for filtering blood in the kidneys. Lastly, goblet cells are mucus-secreting cells that can be found throughout the body, particularly in the respiratory and digestive tracts.
Overall, the body is made up of various types of cells that have different functions and play important roles in maintaining overall health and well-being.
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This question is part of the following fields:
- Histology
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Question 7
Correct
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What is the cutaneous sensory organ that has a histological structure resembling the layers of an onion when viewed in cross-section?
Your Answer: Pacinian corpuscles
Explanation:Types of Skin Receptors
Pacinian corpuscles, free nerve endings, Meissner’s corpuscles, and Merkel cells are all types of skin receptors that play a role in sensory perception. Pacinian corpuscles are located deep in the dermis and are responsible for detecting pressure and vibration. They are made up of concentric rings of Schwann cells surrounding a nerve ending, giving them a distinctive onion-like appearance. Free nerve endings, on the other hand, are primary sensory afferents that are found throughout the dermal tissue and act as pain and temperature receptors.
Meissner’s corpuscles are touch receptors that are primarily located on the hands and feet. They are formed of spirally arranged cells in a fibrous coating, allowing them to detect light touch and changes in texture. Finally, Merkel cells are single cells that are found in the epidermis and function as slowly adapting touch receptors. They are similar in appearance to melanocytes but lack cytoplasmic processes.
In summary, these different types of skin receptors work together to provide us with a complex sensory experience, allowing us to perceive pressure, vibration, pain, temperature, and touch.
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This question is part of the following fields:
- Histology
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Question 8
Incorrect
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What is the cell type in the glomerulus that has a role in phagocytosis?
Your Answer: Granular cells
Correct Answer: Mesangial cells
Explanation:The Structure of the Glomerulus
The glomerulus is composed of glomerular capillaries that are lined by a basement membrane and podocyte processes. Podocytes are connected to the epithelial cells of Bowman’s capsule, which are then connected to the cells of the proximal convoluted tubule. Supporting cells called mesangial cells are located between the capillary endothelial cells and podocytes. These cells produce the extracellular matrix that supports the structure of the glomerulus and remove dead cells through phagocytosis. Additionally, mesangial cells may play a role in regulating glomerular blood flow. Overall, the glomerulus is a complex structure that plays a crucial role in the filtration of blood in the kidneys.
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This question is part of the following fields:
- Histology
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Question 9
Correct
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What does the term carcinoma in situ mean?
Your Answer: Highly dysplastic cells that have not invaded through the basement membrane
Explanation:Carcinoma in Situ: A Non-Invasive Tumor
A carcinoma in situ is a type of tumor that appears malignant under microscopic examination but has not yet invaded through the basement membrane. This membrane is a crucial feature that defines malignancy, and without it, the tumor cannot metastasize. Therefore, local resection is often curative. The cells that make up a carcinoma in situ typically exhibit high-grade dysplasia, which means they have all the characteristics of malignancy.
It’s important to note that benign growths do not invade through the basement membrane, and low-grade dysplasia alone is not enough to define a carcinoma in situ. Additionally, an inherited mutation in an oncogene or tumor suppressor gene can increase the risk of developing malignancy, but it does not necessarily result in a carcinoma in situ.
Overall, a carcinoma in situ is a non-invasive tumor that has the potential to become malignant if it invades through the basement membrane. However, with proper treatment, it can often be cured before it becomes a more serious issue.
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This question is part of the following fields:
- Histology
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Question 10
Correct
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Which cell type provides support to the blood brain barrier through its foot processes?
Your Answer: Astrocytes
Explanation:Glial Cells in the Nervous System
There are various types of supporting cells in the nervous system, including astrocytes, ependymal cells, microglia, oligodendrocytes, and Schwann cells. Astrocytes play a crucial role in supporting the blood-brain barrier by wrapping their long foot processes around every capillary in the brain. This barrier separates the systemic circulation from the cerebral tissue and regulates the movement of water and glucose between them.
Ependymal cells are responsible for producing cerebrospinal fluid (CSF) in the choroid plexus. Microglia have an immune function and are involved in phagocytosis. Oligodendrocytes are responsible for myelinating cells in the CNS, while Schwann cells perform the same function in the PNS.
In summary, glial cells play a vital role in supporting and protecting the nervous system. Each type of glial cell has a unique function, from supporting the blood-brain barrier to producing CSF and myelinating cells. the roles of these cells is crucial in the complex workings of the nervous system.
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This question is part of the following fields:
- Histology
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