Animal Morphology: Introduction and Important MCQs

Ans: c) Dense regular connective tissue.

Explanation: Tendons are made of collagen fibers and connect muscles to bones, ligaments are also made up of collagen fibers and connect one bone to another one. They are both examples of fibrous connective tissue and are connected by parallel bundles of collagen fibers, which gives it a strong and stable structure. Moreover, the fibrous connective tissue is used to provide support to our bones and organs, also works as a shock-absorber for internal organs and bones.

Ans: c) Simple squamous epithelium.

Explanation: Simple squamous epithelium is mostly present at sites where filtration and diffusion occur. It plays a very important role in the absorption and transport of materials. Simple squamous epithelium is found in the endothelium, in the blood linings and walls of lymph capillaries, in the alveoli of lungs, where diffusion of gases rapidly takes place, glomeruli of kidneys where rapid diffusion of waste materials from the blood and vice versa is performed. Simple squamous epithelial cells are flat with flattened and oblong nuclei and it is also known as pavement epithelium. They are important for osmosis, filtration, and diffusion.

Ans: a) Exocrine gland

Explanation: A sebaceous gland is a microscopic exocrine gland that is branched and spherical. These glands produce sebum, an oily, semiliquid mixture of glandular cell debris which contains glycerides, free fatty acids, wax esters, squalene, cholesterol, and cholesterol esters. The sebaceous glands are present on the skin of mammals and they open into the hair follicle to secrete sebum.

Ans: b) Albumin

Explanation: The blood plasma is the straw-colored, viscous, liquid part of human blood that contains water, enzymes, free ions, and proteins. Plasma contains about 90-92% water and 6-8% proteins. The water content is 90% of the blood plasma, the other 10% contains ions, waste materials to be thrown out of the body, enzymes, proteins, nutrients, and dissolved gases. Albumin is a globular protein and constitutes almost 55% of the blood proteins. Albumin maintains the oncotic pressure of plasma and provides assistance i.e. acts as a carrier to lipids and steroid hormones in the blood. 

Ans: a) 3

Explanation: Octopus is an aquatic invertebrate animal of the phylum Mollusca and it has three hearts. This is mainly due to their unusual composition of blood. Octopuses have blood blue in color since the 'haem' i.e. iron in their blood is replaced with copper. They have two peripheral hearts that pump blood through the gills, where oxygen is picked up and another is the central heart that pumps out and circulates oxygenated blood to the rest of the body, organs, and muscles, to provide energy.

Ans: d) Cardiac muscles.

Explanation: The intercalated discs are found in the cardiac muscles, they are also called gap junctions and are made of muscle cells. They are found between the myocardial cells of the heart. The intercalated discs are low-resistance cell membranes that distinguish individual cardiac muscle cells and define their borders. They play a vital role in cell-to-cell signal transmission, which leads to better muscle coordination and proper circulation of blood in the human body.

Ans: a) Yellow elastic fibers are intact.

Explanation: The mummies in Egypt are well preserved even after hundreds and thousands of years because their arteries are still intact. This is due to the presence of yellow elastic connective tissue fibers, which are present in the wall of the lungs, bronchioles, blood vessels, the cartilage of the larynx, and the trachea. The yellow elastic connective tissue fibers have high tensile strength and remarkable elasticity. This is the reason why the arteries in the mummies of Egypt are still intact.

Ans: a) Red blood cells.

Explanation: Hemotoxic venom is a deadly venom to human blood when venom comes in contact with human blood it can cause bleeding, interfere with blood pressure and the ability of blood to clot, and can directly cause hemorrhage. This means the haemotoxic venom attacks the body's circulatory system and destroys red blood cells(RBCs). The term 'haemotoxic' refers to 'haem' + 'toxic' i.e. it is toxic to the blood or hemoglobin. Moreover, hemotoxin causes hemolysis, which is the term used for the destruction of red blood cells(RBCs) or erythrocytes.

Ans: a) Involuntary

Explanation: Smooth muscles are located along the walls of visceral hollow organs like the pancreas, liver, intestine and are spindle-shaped. These organs require constant attention and therefore are involuntary and do not require the body's will. The smooth muscles do not show cross stripes when observed under a microscope and are, therefore, called non-striated. Smooth muscles can be involuntarily contracted or regulated. They line the inner organ walls like the pancreas, liver, blood vessels, intestine, etc. excluding the heart. These muscles are controlled by our nervous system and play a vital role in every location. It helps in controlling the oxygenation of tissues and blood pressure in our body in the blood vessels, it aids in digestion in the gastrointestinal tract, it helps in electrolyte balance to destroy or remove the toxins from our system, in the urinary system. Therefore, without smooth muscles performing involuntary actions our body would fail.

Ans: b) Brain cells

Explanation: Our brain cells are formed and multiplied only for a short time after we were born, which means we can only rely on the number of brain cells we are born with. Moreover, brain neurons are post-mitotic i.e. only a few parts of the brain and neurons will be generated again in the adult human brain. Cell-autonomous factors also play a significant role in determining Central Nervous System(CNS) regeneration failure. CNS neurons do not upregulate growth-associated genes to the same extent as PNS neurons. Therefore, the ability of brain cells to regenerate is limited even in the absence of inhibitors.

Ans: a) Histology

Explanation: The study of tissues is known as Histology. Tissues are a group of cells that acts as an organizational unit of a living being since a group of tissues makes up an organ. These groups of cells forming a tissue have similar origins and functions but are different in structures. It is done by observing and studying various characteristics of tissues under a thin electron microscope. 

Ans: a) White blood cell

Explanation: A macrophage is a type of phagocyte, which is a cell responsible for detecting, engulfing, and destroying pathogens and foreign materials. It is a large phagocytic cell found in a single place lying in the tissues or as a mobile white blood cell at the sites of infection or foreign substances. Thus, macrophages protect the body by engulfing and ingesting harmful materials entering the body and thus, initiating quick immune responses. They also aid the body to develop adaptive immunity.

Ans: b) Earthworms

Explanation: The earthworms have a genus called Pheretima which are hermaphrodites and reproduction in them can only be sexual. The species that belong to the genus Pheretima have clitellum which is a band of glandular tissue. Like most earthworms, these species also have no larval stage, and the development of young is in a cocoon. They are nocturnal and have an aversion to light which is why feeding and reproduction take place at night, they also have to keep their body surface wet like most earthworms to help them in respiration. They irrigate the soil and make it porous which is why they are also known as the farmer's friends. The earthworms belong to a phylum called Annelid. The common name for Pheretima is "Big Earthworm".

Ans: c) Areolar tissue

Explanation: The largest quantity of extracellular material is present in areolar tissue. The extracellular material of the cell-matrix is the substance that is secreted to provide structural and biochemical support to the other cells. Areolar tissue contains the largest amount of extracellular material like fibers and ground substances that support the surrounding cells and fill the space between the cells.

Ans: a) Squids

Explanation: Chromatophores are pigment-containing cells or groups of cells that are found in a number of cold-blooded animals like amphibians, cephalopods, fish, crustaceans, and reptiles. Among the given options, Squid belongs to Class Cephalopoda of phylum Mollusca. Therefore, the squids contain chromatophores in their skin. These cells play an important role in generating skin color and eye color in squids and adjust their body coloration depending on the surroundings such as in times of camouflage or mating behavior. The chromatophores are light-reflecting cells that contain pigment sacs that become visible further as the pigment expands under the skin when small radial muscles pull the sac open.

Chromatophores are pigment-containing cells or groups of cells that are found in a number of cold-blooded animals like amphibians, cephalopods, fish, crustaceans, and reptiles. Among the given options, Squid belongs to Class Cephalopoda of phylum Mollusca. Therefore, the squids contain chromatophores in their skin. These cells play an important role in generating skin color and eye color in squids and adjust their body coloration depending on the surroundings such as in times of camouflage or mating behavior. The chromatophores are light-reflecting cells that contain pigment sacs that become visible further as the pigment expands under the skin when small radial muscles pull the sac open.