Animal Tissues and Histology

(d) Smooth muscle : Wall of intestine

Smooth muscle is found in walls of visceral organs such as the intestine. Tendons are dense regular connective tissue, not areolar. Transitional epithelium lines the urinary bladder (the tip of the nose is cartilage), and the stomach is lined by columnar epithelium.

(b) involuntary, fusiform, non-striated

Smooth muscles are involuntary, spindle-shaped (fusiform), uninucleate and non-striated. Voluntary, striated multinucleate cylindrical fibres are skeletal muscle, and cardiac muscle is involuntary but striated.

(b) facilitate communication between adjoining cells by connecting the cytoplasm for rapid transfer of ions, small molecules and some large molecules.

Gap junctions are channels linking the cytoplasm of adjacent cells. Adhering junctions cement cells together, and tight junctions stop leakage across a tissue, which are the functions in (a) and (d).

(d) Tubular parts of nephrons - Cuboidal epithelium

The proximal and distal convoluted tubules are lined by cuboidal epithelium. Bronchioles have columnar or cuboidal ciliated epithelium (not squamous), salivary ducts are lined by cuboidal/columnar epithelium (not ciliated), and the moist buccal lining is stratified squamous epithelium, not glandular.

(d) Areolar tissue - Loose connective tissue

Areolar tissue and adipose tissue are loose connective tissue. Tendons are dense regular connective tissue, and cartilage (like bone and blood) is specialised connective tissue. So (a), (b) and (c) each name the wrong category.

(c) Movement of macrophages and leucocytes.

Macrophages and leucocytes move by amoeboid movement using pseudopodia, formed by cytoplasmic streaming and actin-based changes. Dust removal in the trachea, ovum transport in the oviduct and food gathering in Paramecium all depend on cilia.

(d) Bronchioles and Fallopian tubes

Ciliated epithelium lines the bronchioles, where it moves mucus and trapped particles up and out, and the Fallopian tubes, where it moves the ovum towards the uterus. The bile duct, pancreatic duct and salivary duct have non-ciliated cuboidal or columnar lining, and the Eustachian tube alone does not rescue the other options.

(b) Goblet Cells

Goblet cells in the mucosal lining secrete mucus, which forms a protective layer over the GI tract epithelium against digestive enzymes and acid. Chief cells secrete pepsinogen, and oxyntic (parietal) cells secrete HCl and intrinsic factor, so both are enzyme/acid secreting and not protective.

(c) proximal convoluted tubule of nephron

The PCT is lined by simple cuboidal brush-border epithelium. The microvilli increase surface area for reabsorption. Intestinal lining is columnar with a brush border, salivary gland ducts have cuboidal epithelium without microvilli, and the Eustachian tube is ciliated columnar.

(b) Columnar epithelial cells

Goblet cells are unicellular mucus-secreting glands that are modified columnar epithelial cells in the lining of the alimentary canal. They are not derived from squamous cells or chondrocytes.

(d) Cartilage

Intervertebral discs between adjacent vertebrae are fibrocartilage, which absorbs shock and allows limited movement. Intercalated discs are found in cardiac muscle and smooth muscle is visceral, so neither fits.

(b) Neuroglia

Neuroglia are supporting cells of nervous tissue, so they belong to neural tissue. Cartilage, blood and adipose tissue are all connective tissues.

(c) (a) - (iv), (b) - (iii), (c) - (i), (d) - (ii)

Bronchioles are lined with ciliated epithelium, goblet cells are unicellular glands (glandular tissue), tendons are dense regular connective tissue, and adipose tissue is a type of loose connective tissue.

(b) Both Statement I and Statement II are false

Ligaments are dense regular connective tissue (collagen fibres in parallel rows), so Statement I is false. Cartilage is a specialised connective tissue with a solid matrix, not dense regular tissue, so Statement II is false.

(c) A-II, B-I, C-IV, D-III

Mast cells lie in areolar connective tissue (loose connective tissue). The inner surface of bronchioles has ciliated epithelium. Blood is a specialised (fluid) connective tissue. The tubular parts of the nephron are lined by cuboidal epithelium.

(d) Skeletal – Biceps; Involuntary – Intestine; Cardiac – Heart

Biceps is a skeletal (striated, voluntary) muscle. Intestinal muscle is smooth and involuntary. The heart has cardiac muscle. In the other options the heart is called smooth, or skeletal muscle is placed in the "bone" or "legs" (wrongly) or smooth muscle in toes.

(d) A-III, B-IV, C-I, D-II

Goblet cells are unicellular glands in the alimentary canal. Compound epithelium lines moist surfaces such as the buccal cavity. Salivary glands are multicellular exocrine glands. The pancreas has endocrine (hormone-secreting) glandular epithelium as well.

(c) Communication among the cells is performed by intercalated discs

This statement is wrong. Intercalated discs, with gap junctions, are characteristic of cardiac muscle. Smooth muscle is non-striated, involuntary and found in walls of blood vessels and visceral organs.

(b) Tight junctions and Gap junctions, respectively.

Tight junctions seal neighbouring cells and stop leakage of substances across a tissue. Gap junctions connect the cytoplasm of adjacent cells and allow rapid transfer of ions and small molecules. Adhering junctions only cement cells together.