Integrated Histology Part II PDF

# Integrated Histology Part II By Dr. Morsi ## Connective Tissue ### Edema - An increase in the volume of the tissue fluid. - This balance is maintained by two forces: the hydrostatic pressure (blood pressure) of the arterioles that initially pushes the water out into the interstitium and the osm...

# Integrated Histology Part II By Dr. Morsi ## Connective Tissue ### Edema - An increase in the volume of the tissue fluid. - This balance is maintained by two forces: the hydrostatic pressure (blood pressure) of the arterioles that initially pushes the water out into the interstitium and the osmotic pressure (plasma proteins) of the terminal capillaries and venules that return water back into the vessels. - Excess fluid is removed through lymphatics to thoracic duct. - Disruption of any aspect of this balance may result in edema and excess accumulation of fluid in the connective tissue. ### Anaphylaxis (hypersensitivity reaction) - An acute inflammatory reaction involving multiple organs (skin, respiratory system) as the result of mast cell and basophil degranulation in response to an allergen exposure (contact, injection, inhalation, ingestion). - There is skin itching, redness, swelling, airway edema, bronchospasm, vasodilation. A 4-year-old girl was exposed to a bee sting while playing in the garden. A few minutes later, she experienced skin papules associated with redness and itching. Which CT cell of the following is concerned with this reaction due to histamine release? a) Pigment cells b) Mast cells c) Lymphocytes d) Plasma cells e) Don't know ### Scurvy - A nutritional disease due to prolonged vitamin C deficiency that results in impaired collagen fibers formation, negatively affecting connective tissue structure and function. - So, organs with high collagen content will suffer leading to bleeding gums, brittle skin, and weak fragile bone. A 12-year-old male student recently suffered from repeated bleeding gums on the usual teeth brushing. He has a past medical history of malnutrition. Which of the following could explain the current bleeding? a) Aggressive teeth-brushing b) Weak connective tissue due to vitamin C deficiency c) Inherited bleeding disorder d) Bad oral hygiene ### Marfan Syndrome - Genetic disorder of elastic fibers (in aorta, heart, eye, skin) characterized by abnormal fibrillin formation resulting in immature and inefficient elastic fiber formation. - Fibrillin is important for maturation of elastic fibers. - Clinically, affected persons are tall stature, have caved-in chest, long fingers, dislocated eye lens, and aortic aneurysm. ## Muscle ### Myasthenia Gravis **Definition:** - Autoimmune disease characterized by fluctuating weakness of striated muscles that worsens with repeated activity. **Pathophysiology: ** - Autoimmune dysfunction – production of autoantibodies directed against acetylcholine receptors (Anti-AchR) - decrease in the Ach receptors at the post synaptic membrane - impairment of the neuromuscular transmission ## Cartilage & Bone ### Osteoarthritis - Gradual degenerative loss of the articular cartilage affecting weight bearing joints (hip, knee, and ankles). - Slowly progress with age. - The cartilage surface becomes rough with fibrillation (papillary appearance) and eburnation (exposure of the subchondral bone). ### Osteoporosis - Age-related loss of bone calcium density in all persons. - Women are commonly affected after menopause due to estrogen loss. - Affected bone is fragile and easily fractured with minimal force. - Treated by estrogen and calcium. ### Osteopetrosis - Genetic disorder affecting osteoclast structure (lack ruffled border) and function. - There is bone formation/resorption imbalance. - Unlike osteoporosis, the affected bone is more dense and thick causing narrowing of bone marrow spaces and bone foramina. - Clinically, there are anemia (decreased marrow space), blindness, deafness (damage to the cranial nerves as the foramina of the skull become narrow impinging on the nerves). ### Achondroplasia - Autosomal dominant genetic disorder. - Affected persons are dwarf (short stature) and their parent are with normal height. - Histologically, in the epiphyseal plate, the zone of proliferation is abnormally short, and the chondrocytes are arranged side-by-side than longitudinally, forming cell nests rather than columns of chondrocytes. - Consequently, the zone of hypertrophy is also adversely affected, leading to dwarfism (failure of bone growth). ### Disc prolapse - Herniation - Occur between the age 30-40 years. - Pathology: degenerative changes affecting: - Hydration of the nucleus pulposus (mucoid CT). - Strength of collagen, leading to weakening of the anulus fibrosus (fibrocartilage). - So, the degenerated nucleus pulposus loses its cushioning ability and exerts uneven pressure on the surrounding weak anulus; extruding the nucleus pulposus through the weakened annulus (herniation). - Affect neck, lumbar/sacral regions causing back pain and other neurologic symptoms because of ## Blood ### Sickle Cell Anemia - An autosomal recessive disorder leading to the production of defective hemoglobin (HbS instead of HbA) — aggregate and polymerize when deoxygenated. - The red blood cells become longer and curved (crescent shaped sickle cells) — loss of malleability and malfunction causing ischemia of the tissues and severe pain. - Symptoms and signs include anemia, vasoocclusive complications, and chronic hyperbilirubinemia. - Dehydration, infection, hypertonicity, and decreased pH can trigger an onset in a sickle cell patient. ## Nervous Tissue ### Multiple Sclerosis - Autoimmune demyelinating disease of the CNS. - Causes: Genetics and childhood infections. - Pathogenesis: The immune system destroys the myelin sheath. - Signs and symptoms depend on the severity and location of affected nerves. It may include numbness or weakness of limbs, visual impairments (double or blurring vision), unusual sensations in certain body parts, tremor, and fatigue. - Histologically, there are multiple plaques of demyelination, loss of oligodendrocytes, scarring, and possible axonal injury and loss. - Glucocorticoids and immunomodulatory agents are treatments of first choice. ### Alzheimer Disease - is the most common form of dementia in the elderly. - Affected patients have progressive memory loss, personality changes, and cognitive impairments. - Histologically, the cerebral cortex shows extracellular deposition of amyloid plaques, intracellular neurofibrillary tangles, and loss of neurons and synapses. - Anatomically, there is atrophy of the affected cortical regions. - There is NO actual treatment. However, psychosocial therapies and supportive caregiving are needed. ## Skin ### Psoriasis - Psoriasis is a chronic inflammatory skin disease characterized by pink to salmon-colored plaques with silver scales. - Occur as a disturbed immune response. - Symptoms and signs include itching, joint pain, nail pitting, and nail discoloration. - Histologically (illustrated), there are:- - Thickened epidermis (increased epidermal turnover) leading to extensive overlying parakeratotic scales. - Microabscesses form within the parakeratotic areas of stratum corneum. - Micropustules (within the stratum granulosum and spinosum layers.