GSEB Class 11 Biology Solutions Chapter 7 Structural Organisation in Animals

Question 1. Answer in one word or one line.
(i) Give the common name of Periplaneta Americana.
(ii) How many spermathecae are found in earthworms?
(iii) What is the position of ovaries in cockroaches?
(iv) How many segments are present in the abdomen of the cockroach?
(v) Where do you find Malpighian tubules?
Answer:
(i) Cockroach
(ii) Two
(iii) Two large ovaries are situated laterally in the 2nd to 6th abdominal segment.
(iv) Ten segments.
(v) Malpighian tubules serve as the primary excretory organs for cockroaches.
In simple words: Just give a short, direct answer for each part, often a single word or a brief sentence, stating the fact.

Exam Tip: For one-word/one-line answers, ensure your response is precise and directly answers the question without additional information.

Question 2. Answer the following:
1. What is the function of nephridia?
2. How many types of nephridia are found in earthworms based on their location?
Answer:
1. Nephridia help control the amount and makeup of body fluids. A nephridium begins like a funnel that gathers extra fluid from the coelomic space. This funnel links to a tube-shaped part of the nephridium, which moves waste materials out through a pore in the body wall and into the digestive system.
2. Earthworms have three primary categories of nephridia:
• **Septal nephridia:** These are found on both sides of the septa (walls) between segments, from segment 15 to the last. They open directly into the intestine.
• **Integumentary nephridia:** These are connected to the inner lining of the body wall, from segment 3 to the final segment. They open onto the body's outer surface.
• **Pharyngeal nephridia:** These appear as three pairs of tufts (small clusters) located in the 4th, 5th, and 6th segments. All these different kinds of nephridia generally have a similar basic structure.
In simple words: Nephridia manage fluid balance and waste removal in earthworms. There are three types: septal (opening into the gut), integumentary (opening onto the skin), and pharyngeal (in specific front segments), all having a similar look.

Exam Tip: When describing functions, use action verbs and specify the "what" and "how." For types, list each one with its location and key characteristic clearly.

Question 3. Draw a labeled diagram of the reproductive organs of an earthworm.
Answer:

Exam Tip: When drawing biological diagrams, ensure all key structures are clearly visible and accurately labeled. Use clean lines and appropriate proportions.

Question 4. Draw a labeled diagram of the alimentary canal of a cockroach.
Answer:

Exam Tip: Pay attention to the order of organs in the alimentary canal (foregut, midgut, hindgut) and correctly place accessory structures like salivary glands and Malpighian tubules.

Question 5. Distinguish between the followings:
(a) Prostomium and peristomium
Answer: The prostomium is the very front part of an earthworm's head, which is not considered a true segment because it lacks the typical organs of an Annelida. In contrast, the peristomium is the first true segment of the earthworm's body, and this is where the main body segmentation begins.
In simple words: The prostomium is the small fleshy part at the very front of an earthworm, but it's not a real body segment. The peristomium is the actual first body segment where the rest of the worm's segments start.

Exam Tip: For distinction questions, clearly state the definition and key characteristics of each term, highlighting their differences concisely.

Question 5. Distinguish between the followings:
(b) Septal nephridium and pharyngeal nephridium
Answer: Septal nephridia are found on both sides of the intersegmental walls from segment 15 to the last segment, and they open into the intestine. Pharyngeal nephridia are present as three paired tufts (clusters) in the 4th, 5th, and 6th segments. Structurally and functionally, both types are quite similar.
In simple words: Septal nephridia are found at the back part of the earthworm and connect to the gut, while pharyngeal nephridia are in the front segments and look like small bunches. They both work similarly.

Exam Tip: When distinguishing between similar structures, focus on their specific locations and any differences in their connections or general arrangement.

Question 6. What are the cellular components of blood?
Answer: Blood is a liquid connective tissue that contains plasma, along with several cellular elements such as red blood cells, white blood cells, and platelets.
In simple words: Blood is a fluid that carries plasma, red blood cells, white blood cells, and platelets.

Exam Tip: Remember to list all three main cellular components of blood in addition to plasma to score full marks.

Question 7. What are the following and where do you find them in the animal body.
(a) Chondrocytes
Answer: Chondrocytes are the cells that make up cartilage tissue.
In simple words: Chondrocytes are the cells found within cartilage.

Exam Tip: When asked to identify cells, state what tissue they belong to for a complete answer.

Question 7. What are the following and where do you find them in the animal body.
(b) Axons
Answer: Axons are long, thin projections of nerve cells (neurons) that carry electrical signals away from the neuron's cell body. They are primarily located in the nervous system, forming nerve fibers throughout the brain, spinal cord, and peripheral nerves across the body.
In simple words: Axons are the long parts of nerve cells that send signals away from the cell. You find them in the brain, spinal cord, and nerves all over the body.

Exam Tip: For terms like 'axon', provide both a brief description of what it is and its primary location within the body.

Question 7. What are the following and where do you find them in the animal body.
(c) Ciliated epithelium
Answer: Ciliated epithelium is found in the inner lining of bronchioles (small air passages in the lungs). The cilia (tiny hair-like structures) on these cells help to trap and clear foreign particles like dust.
In simple words: This type of tissue with tiny hairs is in the breathing tubes of the lungs. The hairs catch and remove dirt and other unwanted bits.

Exam Tip: When describing epithelial tissues, always include their location and a key function related to that location.

Question 8. Describe various types of epithelial tissue with the help of labeled diagrams.
Answer: Epithelial tissue forms the covering of all body surfaces, lines body cavities and hollow organs, and is the major tissue in glands. It performs various functions, including protection, secretion, absorption, excretion, filtration, diffusion, and sensory reception. Here are the main types with their characteristics:
**Simple Epithelium (Single Layered)**
• **Squamous:** These cells are flat and appear scale-like, forming a single thin layer. They create a smooth boundary and are commonly found in the walls of blood vessels, facilitating easy diffusion.
• **Columnar:** These are tall, slender cells with nuclei usually located at their base. They are found lining the intestine, where they are involved in absorption and secretion.
• **Cuboidal:** These cells are cube-shaped. They are involved in secretion and absorption and are located in the ducts of glands and the tubular parts of nephrons in the kidneys.
• **Glandular:** This type of epithelium contains glands, which can be either exocrine (secreting substances onto a surface) or endocrine (secreting hormones into the bloodstream).
• **Ciliated:** These are columnar or cuboidal cells that have cilia (small hair-like projections) on their free surface. Cilia assist in moving particles or mucus in a particular direction and are present in places like the fallopian tubes.
**Compound Epithelium**
• This tissue is made up of more than one layer of cells. Its main role is to offer protection against chemical and mechanical stress, found in areas subjected to wear and tear.

Exam Tip: For each type of epithelial tissue, specify its shape, the number of cell layers, its typical location in the body, and its main function to ensure a comprehensive answer.

Question 9. Distinguish between the followings:
(a) Simple epithelium and compound epithelium
Answer: Simple epithelium is made up of just one layer of cells, while compound epithelium is composed of several layers of cells.
In simple words: Simple epithelium has one layer of cells, but compound epithelium has many layers.

Exam Tip: The fundamental difference between simple and compound epithelium lies in the number of cell layers, which directly relates to their primary functions (absorption/secretion vs. protection).

Question 9. Distinguish between the followings:
(b) Cardiac muscle and striated muscle
Answer: Cardiac muscles are exclusively found in the heart's walls. They have a special contractile ability that helps the heart pump blood. Striated muscles, however, are located near joints that move parts of the body, and their job is to enable the movement of organs such as hands and feet.
In simple words: Cardiac muscles are only in the heart and help it pump. Striated muscles are near joints and help parts like arms and legs move.

Exam Tip: When differentiating muscle types, always specify their location, appearance (striated/non-striated), and whether their action is voluntary or involuntary (though not explicitly asked here, it's a common distinction).

Question 9. Distinguish between the followings:
(c) Dense regular and dense irregular connective tissues
Answer: Both dense regular and dense irregular connective tissues have tightly packed fibers and cells called fibroblasts. The main difference lies in how their fibers are arranged. In dense regular connective tissues, collagen fibers are arranged in parallel rows between bundles of fibers. Tendons (which connect muscles to bones) and ligaments (which join bones to other bones) are good examples of this tissue. Dense irregular connective tissue has fibroblasts and many fibers arranged in different directions. This tissue is typically found in the skin.
In simple words: Dense regular tissue has fibers neatly lined up, like in tendons and ligaments. Dense irregular tissue has fibers crisscrossing in many directions, like in the skin.

Exam Tip: Highlight the arrangement of collagen fibers (parallel vs. irregular) and provide a clear example for each type of dense connective tissue.

Question 9. Distinguish between the followings:
(d) Adipose and blood tissue
Answer: Adipose tissue is a type of loose connective tissue primarily situated beneath the skin. Its cells are specially adapted to store fats. Any extra nutrients not immediately used are changed into fats and kept in this tissue. Blood, on the other hand, is a liquid connective tissue. Its main job is to carry gases, nutrients, and waste products throughout the body.
In simple words: Adipose tissue stores fat under the skin, converting extra nutrients into fat. Blood is a liquid tissue that moves gases, food, and waste around the body.

Exam Tip: For distinctions involving different tissue types, clearly state their primary composition, typical location, and main function.

Question 9. Distinguish between the followings:
(e) Simple gland and compound gland
Answer: A simple gland consists of a single cell, whereas a compound gland is composed of multiple cells.
In simple words: A simple gland is made of one cell, while a compound gland is made of many cells.

Exam Tip: The key difference between simple and compound glands lies in their cellular organization: single-celled versus multicellular, which often influences their complexity and secretory capacity.

Question 10. Mark the odd one in each series:
1. Areolar tissue; blood; neuron; tendon
2. RBC, WBC; platelets; cartilage
3. Exocrine; endocrine; salivary gland; ligament
4. Maxilla; mandible; labrum; antennae
5. Protonema; mesothorax; metathorax; coxa
Answer:
1. Neuron
2. Cartilage
3. Ligament
4. Labrum
5. Protonema
In simple words: In each group, find the one item that doesn't belong with the others.

Exam Tip: To identify the odd one out, first determine the common category shared by most items, then pinpoint the one that falls outside that category.

Question 11. Match the terms in Column I with those in Column II
**Column I**
(a) Compound epithelium
(b) Compound eye
(c) Septal nephridia
(d) Open circulatory system
(e) Typhlosole
(f) Osteocytes
(g) Genitalia
**Column II**
(i) Alimentry canal
(ii) Cockroach
(iii) Skin
(iv) Mosaic vision
(v) Earthworm
(vi) Phallomere
(vii) Bone
Answer:
(a) iii
(b) iv
(c) v
(d) ii
(e) i
(f) vii
(g) vi
In simple words: Match each term from the first list with its correct partner from the second list.

Exam Tip: When matching, eliminate options you are sure about first, and for terms you are less certain of, try to find logical connections or associations.

Question 12. Mention briefly the circulatory system of earthworms.
Answer: **Blood vascular system:** The earthworm (Pheretima) has a closed type of blood vascular system, meaning blood is always contained within blood vessels, capillaries, and the heart. Because it's a closed system, blood remains inside the heart and vessels. Contractions help blood move in one direction. Smaller blood vessels provide blood to the gut, nerve cord, and body wall. Blood glands are present in the 4th, 5th, and 6th segments. These glands create blood cells and hemoglobin, which dissolves in the blood plasma. Blood cells can also perform phagocytosis (engulfing foreign particles). Earthworms do not possess specialized organs for breathing. Instead, respiratory gas exchange happens through their moist body surface into their bloodstream.
In simple words: Earthworms have a closed blood system, so blood stays in vessels and a simple heart pumps it. Blood glands in some segments make blood cells and hemoglobin. They breathe through their skin, not special organs.

Exam Tip: When describing organ systems, always mention the type (e.g., closed circulatory), key components, and major functions, including any unique adaptations.

Question 13. Draw a neat diagram of the digestive system of the frog.
Answer:

Exam Tip: For diagrams, accuracy in organ placement and clear, legible labels for all components are crucial for scoring well.

Question 14. Mention the function of the following
(a) Ureters in frog
Answer: In frogs, the ureters serve as a urinogenital duct, meaning they transport both urine and reproductive products. They open into the cloaca. In female frogs, the ureters and oviducts open separately into the cloaca.
In simple words: In frogs, ureters carry both urine and reproductive cells to the cloaca. In females, these open separately from the egg tubes.

Exam Tip: When asked about dual-function organs like ureters in frogs, always specify both their excretory and reproductive roles.

Question 14. Mention the function of the following
(b) Malpighian tubules
Answer: Malpighian tubules in cockroaches are responsible for excretion. Each tubule is lined by glandular and ciliated cells. These cells absorb nitrogenous waste products and then convert them into uric acid, which is then removed through the hindgut.
In simple words: Malpighian tubules help cockroaches get rid of waste. Their special cells take in nitrogen waste and change it into uric acid, which then leaves the body.

Exam Tip: For excretory organs, ensure you name the specific waste product they handle (e.g., uric acid) and the main process involved (absorption, conversion, excretion).

Question 14. Mention the function of the following
(c) Body wall an earthworm
Answer: The body wall of an earthworm is covered on the outside by a thin, noncellular cuticle. Beneath this cuticle are the epidermis, two layers of muscle, and an innermost coelomic epithelium. The epidermis consists of a single layer of columnar epithelial cells that contain secretory gland cells.
In simple words: An earthworm's body wall has a thin outer skin, then muscle layers, and an inner lining. The epidermis contains special cells that make secretions.

Exam Tip: When describing the body wall, list its layers in order from exterior to interior and mention the key features of each layer.