a. Simple squamous epithelium
c. Reproduction
b. Squamous epithelium
a. Pseudostratified epithelium
a. Brown adipose tissue
d. I – d, II – c, III – b, IV – a
d. Both (b) and (c)
d. Trachea
a. Collagen
a. Tight junction
b. Brown fat
Pseudostratified epithelial cells are columnar but unequal in size. Although the epithelium is single-layered yet it appears to be multilayered due to the fact that nuclei lie at different levels in different cells.
White adipose tissue
Brown adipose tissue
1. They have less number of Mitochondria.
They have more numbers of mitochondria.
2. They store nutrients
It is used to heat the bloodstream to warm the body.
Blood is considered as a typical connective tissue because it is the fluid connective tissue containing plasma, RBCs, WBCs and platelets. It functions as the transport medium for the cardiovascular system carrying nutrients, nitrogenous wastes, and respiratory gases throughout the body.
Elastic Fibres
Elastic connective tissue
1. It is found in the skin as the leathery dermis and forms fibrous capsules of organs such as kidneys bones and cartilages.
This is present in tendons that attach skeletal muscles to bones and ligaments.
2. It allows recoil of tissues following stretching.
It attaches one bone to another.
3. It maintains the pulsative flow of blood through the arteries and the passive recoil of lungs following inspiration.
It is able to with stand tension exerted in many directions and provides structural strength.
Functions
Tissues
1. Protection
Squamous epithelium. In heart lungs and blood vessels as a protective covering.
2. Absorption
Columnar epithelium. (It lines the digestive track)
3. Secretion
Cuboidal and columnar epithelium. Salivary gland endocrine glands.
4. Filteration
Squamous epithelium glomerulus.
Types of epithelium
Characters
1. Squamous epithelium
Made up of a single thin layer of flattened cells with irregular boundaries.
2. Cuboidal epithelium
Made up of a single layer of cube-like cells.
3. Columnar epithelium
Made up of a single layer of tall cells with round to
oval nuclei at the base.
4. Ciliated epithelium
It bears cilia on their free surfaces.
5. Nonciliated epithelium
There is no cilia on the free surfaces of columnar
epithelium
6. Pseudostratified epithelium
Columnar but unequal in size
7. Compound epithelium
Made up of more than one layer of cells.
Part II
11th Bio Zoology Guide Tissue Level of Organisation Additional Important Questions and Answers
I. Choose The Best Options
It is made up of more than one layer of cells.
Uses:
It helps in providing protection against chemical and mechanical stresses.
Location:
Buccal cavity, Pharynx salivary glands, Pancreatic ducts
Types:
* Stratified squamous epithelium. It is present in the dry epidermis of the skin,
* Keratinized type-Mouth and vagina.
* Non – Keratinized type
* Stratified cuboidal epithelium – Sweat glands, Mammary gland
* Columnar epithelium-Pharynx urethra
* Transitional epithelium – Ureters, urinary bladder.
Each muscle is made of long, cylindrical fibres. They are composed of fine fibrils called myofibrils. Muscle fibres contract and relax. Skeletal muscle is attached to skeletal bones. It is striped or striated. It is a voluntary muscle. The smooth muscle fibres are fusiform and do not have striations. It is an involuntary muscle. Cardiac muscle tissue is present in the heart. It is striated and branched and involuntary.
If two or more organs perform common physical and chemical functions they are called “organ systems”.
It is a sheet of cells that covers the body surface or lines the body cavity.
Types:
* Simple epithelium
* Compound epithelium
- Outer covering
- Protection
- Absorption
- Excretion
- Secretion
It consists of isolated glandular cells.
(Eg.) Goblet cells of the alimentary canal.
- Merocrine
- Holocrine
- Apocrine
Connective tissues originated from Mesoderm.
Types of connective tissue: Bones and blood, Cartilage.
- Binding
- Support
- Protection
- Insulation
- Transportation
- Collagen
- Elastic
- Reticular
Each muscle is made of many long cylindrical fibers arranged in parallel arrays known as myofibrils.
Smooth muscles are involuntary as their functions cannot be directly controlled. (Eg.) Blood vessels, Stomach intestine
The unit of nervous system is neuron. Cells:
* Excitable cells
* Neuroglial cells.
Uses:
Protection, secretion and absorption.
Site of occurrence:
Ciliated epithelium — Respiratory tract. Nonciliated epithelium – Epididymis urethra of male.
The areolar connective tissue acts as a reservoir of water and salts for the surrounding body tissue. Hence it is called tissue fluid.
Composition:
* Fibroblasts
* Macrophages
* Mast cells
Defect in the synthesis of collagen in the joints heart values organ walls and arterial walls.
It is a defect that affects collagen and results in facial abnormalities.
It is a life-threatening soft tissue tumour of the head neck and urinogenital tract.
The immune cell attack and inflame the membranes around the joints.
It is a disease in which progressive inability to secrete saliva and tears.
It is a long narrow muscle run from the elbow to the wrist and is important for hanging and climbing in primates.
It is a degenerative disorder of the nervous system that affects movement often including tremors.
It is a chronic neurodegenerative disease which includes the symptoms of difficulty in remembering recent events.
It is an examination of tissue or liquid removed from a living body to discover the presence cause or extent of a disease.
It is a dissection of a dead body (Post – mortem) examination to discover the cause of death or the extent of disease.
It is the field of science that effectively uses histological techniques to trace out crimes.
The unicellular epithelium is made up of a single layer of cells. These are seen in the organs which do the functions of absorption secretion and filtration.
It is the unit of secretion.
This is composed of big adipose tissue in the centre and the cytoplasm is seen as a thin covering layer.
The mineral hydroxyapatite is a substrate of bone tissue.
(3 marks)
III. Short Questions
All cells of epithelia are held together with little intercellular material forming specialized junctions. These provide structural and functional links between the cells. Three types of cell junctions, tight, adhering and gap junctions are found in animal tissues.
Tight junctions help to stop substances from leaking across the tissue. Adhering junctions cement the neighbouring cells together. Gap junctions facilitate the transfer of ions, small and big molecules between the adjoining cells by connecting the cytoplasm of these cells.
Dense regular connective tissue
Dense irregular connective tissue
1.Collagen fibres are present.
Collagen fibres are present.
2. Fibroblast cells are present.
Fibroblast cells are present.
3. it connects the bone with skeletal muscles,
It is able to withstand tension exerted in many direction and provides structural strength.
Muscles are of three types.
* Skeletal muscles
* Smooth muscles
* Cardiac muscles.
1. Skeletal muscles:
These muscle fibres are bundled together in a parallel fashion.
Location: They are closely attached to skeletal
bones.
2. Smooth muscles:
These fibres are tapered at both ends and do not show striations.
Location: Blood vessels stomach intestine.
3. Cardiac Muscles:
In these muscles, cell junctions fuse the plasma membranes of cardiac muscle cells and make them stick together.
Location: Heart.
* The compound epithelium is made up of multilayered cells.
* These protect organs against chemical and mechanical stresses.
* These cover the dry surface of the skin, the moist surface of the buccal cavity, pharynx, inner lining of ducts of salivary glands, and pancreatic ducts.
(5 marks)
IV. Essay Questions
c. Ants – Adipocytes
b. Bone tissue
a. Minute fibrils of muscle fibres
b. I – d, II – c, III – b, IV – a
(2 marks)
II. Very Short Questions
Some of the epithelial cells get specialized for secretion they are called the glandular epithelium.
I. Based on cellular structure
They are classified as Unicellular (Eg.) Goblet cells of the alimentary canal. Multicellular (Eg.) Salivary gland
II. Based on mode of pouring
Exocrine glands – The products are released through ducts. (Eg.) Mucus secreting glands, Saliva secreting glands.
Endocrine glands – They do not have ducts. Their secretions directly secreted into the fluid bathing the glands.
(Eg.) Pituitary gland.
a) Exocrine glands based on cellular nature
* Unicellular
* Multicellular
b) Exocrine based on the structure
* Simple
* Compound glands
c) Based on their secretary units
* tubular
* alveolar
* tubulo alveolar
d) Based on their mode of secretion
* Merocrine
* Holocrine
* Apocrine.