Animal Tissue
Short Questions
1. What is a tissue?
Answer: A group of cells with similar embryonic origin, structure, and function.
2. What is histology?
Answer: The study of the structure and arrangement of tissues.
3. Where is squamous epithelial tissue located?
Answer: In blood vessels, alveoli, and coelom.
4. What is the main function of epithelial tissue?
Answer: Protection, absorption, transport, filtration, and secretion.
5. What is the protein in cartilage matrix?
Answer: Chondrin.
6. What is the function of ciliated epithelium?
Answer: Moves materials in a specific direction and prevents foreign particle entry.
7. What is the role of fibroblasts in areolar tissue?
Answer: Produce fibres and matrix.
8. Where is hyaline cartilage found?
Answer: At ends of long bones, epiglottis, trachea, ribs, larynx, and hyoid.
9. What is the matrix of bone made of?
Answer: Ossein with hydroxyapatite.
10. What are sarcomeres in skeletal muscles?
Answer: Functional units of myofibrils with actin and myosin.
11. Why are smooth muscles called non-striated?
Answer: They lack striations due to unorganized myofibrils.
12. What is myoglobin in muscles?
Answer: A red pigment that carries oxygen in muscle cells.
13. What is the function of a multipolar neuron?
Answer: Conducts impulses in the brain and spinal cord.
14. What is saltatory conduction in neurons?
Answer: Impulse jumps between Nodes of Ranvier in myelinated fibres.
15. What are intercalated discs in cardiac muscles?
Answer: Transverse thickenings of sarcolemma connecting adjacent fibres.
Long Questions
1. Explain the structure and function of squamous epithelial tissue.
Answer: Squamous epithelial tissue consists of flat, thin, polygonal cells with serrated margins and a central spherical or oval nucleus, resembling pavement tiles. It functions in protection, absorption, transport, filtration, and secretion. This tissue is found in blood vessels, alveoli, and coelom, where its thin structure facilitates diffusion and filtration.
2. Describe the role of glandular epithelium in the body.
Answer: Glandular epithelium, composed of columnar, cuboidal, or pyramidal cells with secretory granules, forms unicellular (e.g., goblet cells) or multicellular glands (e.g., salivary glands). It secretes mucus, enzymes, or hormones, with exocrine glands releasing secretions via ducts and endocrine glands into the bloodstream. This tissue lubricates respiratory/digestive tracts and regulates bodily functions through hormone secretion.
3. What are the characteristics of areolar connective tissue?
Answer: Areolar connective tissue has a semisolid, gelatinous matrix containing white collagen fibres for tensile strength and yellow elastin fibres for elasticity. It includes fibroblasts (produce matrix), mast cells (secrete heparin/histamine), macrophages (phagocytic), and adipocytes (store fat). Found under skin and between organs, it acts as packing material, connects tissues, and aids healing.
4. Differentiate between hyaline and elastic cartilage.
Answer: Hyaline cartilage, with a bluish-white, gel-like matrix and perichondrium, is elastic and compressible, found in trachea and long bone ends, reducing friction. Elastic cartilage, also with perichondrium, contains elastic fibres for flexibility, located in the ear lobe and nose tip to maintain shape. Hyaline is more rigid, while elastic is more flexible due to its fibre composition.
5. How does the structure of bone support its function?
Answer: Bone has a hard matrix (ossein with hydroxyapatite) arranged in concentric lamellae, enclosed by periosteum, with lacunae housing osteocytes connected by canaliculi. The haversian system in compact bones supports blood vessels and nerves, enhancing strength. This structure provides support, protection, and facilitates movement in the skeletal system.
6. Explain the histological structure of skeletal muscles.
Answer: Skeletal muscles consist of fasciculi wrapped by epimysium, with each fasciculus covered by perimysium, containing multinucleate myofibres with peripheral nuclei. Myofibrils within sarcoplasm have sarcomeres with A (myosin + actin) and I (actin) bands, giving a striated appearance. This structure enables quick, strong voluntary contractions for body movements.
7. What are the features of cardiac muscles that make them unique?
Answer: Cardiac muscles combine striated and non-striated traits, with uni-nucleate, branched fibres connected by intercalated discs for rapid stimulus transfer. They are involuntary, striated, and some are myogenic, capable of self-generating impulses. Found in the heart’s myocardium, they ensure synchronized contractions for heart function.
8. Describe the structure of a multipolar neuron.
Answer: A multipolar neuron has a star-shaped cyton with neuroplasm containing Nissl’s granules, a nucleus, and multiple dendrons carrying impulses to the cyton via dendrites. A single axon, bounded by axolemma and often myelinated with Nodes of Ranvier, conducts impulses away. This structure supports complex impulse conduction in the brain and spinal cord.
9. What are cell junctions, and how do they function in epithelial tissue?
Answer: Cell junctions are complexes connecting epithelial cells laterally and to the basement membrane, ensuring tissue integrity. Tight junctions prevent diffusion, gap junctions allow molecular exchange, hemidesmosomes anchor to the basement membrane, desmosomes provide mechanical strength, and adherens junctions aid signaling. They maintain polarity, communication, and structural stability in epithelial layers.
10. Why is connective tissue considered the most versatile tissue in the body?
Answer: Connective tissue, including loose (areolar, adipose), dense (tendons, ligaments), supporting (cartilage, bone), and fluid (blood, lymph) types, binds and supports other tissues. Its diverse cells (fibroblasts, adipocytes) and matrix (gelatinous to hard) enable functions like insulation, protection, and nutrient transport. Its widespread presence and vascularity (except cartilage) make it essential for structural and functional support.
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