Structural Organisation in Animals 2

Question 1

what is the origin of connective tissue

Answer 1

Origin- Mesodermal

Question 2

what is matrix of connective tissue

Answer 2

Also known as Ground substance and is composed of
mucopolysaccharide (modified polysaccharide) present in
the form of Hyaluronic Acid.

Question 3

cells present in connective tissue

Answer 3

(i) fibroblast cells
(ii) mast cells
(iii) macrophage
(iv)

Question 4

what are fibroblast cells and what is their function

Answer 4

• Largest cells of connective tissue and most maximum in number
• Irregular in shape due to long cytoplasmic processes.
• Cytoplasm is rich in rough ER (producing protein fibres)
• Primary function is to produce protein fibres.
  Secrete most of the matrix of Connective Tissue
  (Chief matrix producing cell).

Question 5

what are macrophages

Answer 5

2nd largest in size
* 2nd maximum in number
Amoeboid cells, with
Kidney Shaped Nucleus
*Cytoplasm is agranular but appears to be granular due
to more number of lysosomes
* Phagocytic in nature. Destroy microbes by phagocytosis
*Also called scavengers of connective tissue because they
destroy dead or damaged cells to clean connective tissue

Question 6

what are mast cells

Answer 6

Small and amoeboid cells
with S-shaped nucleus.
Secrete histamine, serotonin & heparin.
Secrete small amount of matrix in connective tissue.
Histamine - amino acid derivative, vasodilator,
inflammation
Serotonin - amino acid derivative, vasoconstrictor
Heparin- mucoploysaccharide, natural anticoagulant

Question 7

what are types of fat cells

Answer 7

(i) Monolocular Adipocyte
* Forms White fat
* Single, large, central fat globule is present.
* Cytoplasm and nucleus becomes peripheral.

(ii)Multilocular - Adipocyte
* Forms Brown fat
*Many, small, fat granules distributed in cytoplasm around
nucleus
* Cytoplasm is more

Question 8

what are lymphocytes

Answer 8

Centrally located large nucleus and hence cytoplasm
becomes peripheral.
Key cell of immune system and is involved in production of
antibodies
it has clear cytoplasm

Question 9

what are plasma cells

Answer 9

Small amoeboid cells
* In these cells rounded nucleus is present in which chromatin
material is arranged like spokes (radial rows) in wheels so they are
called as cart wheel cells
* Also called clones of lymphocytes as these are formed by division of
lymphocytes

Produce and transport antibodies

Question 10

what is collagen fibres

Answer 10

▪ Made up of collagen protein
(Most abundant protein in animal kingdom)
▪Wavy, unbranched, inelastic, tough fibres
arranged in bundles (fascia)
▪ On boiling they yield gelatin

Question 11

what is elastic fibres

Answer 11

▪ Composed of elastin protein

▪ Branched but arranged singly
▪ Maximum elasticity is present
▪ Highly resistant to chemicals

▪ On boiling they do not yield gelatin

Question 12

what are reticular fibres

Answer 12

Composed of reticulin protein
▪Highly branched fibres which always form dense network
▪Delicate fibres, elasticity absent
▪Mainly found in lymphoid organs such as spleen, lymph
nodes etc.

Question 13

describe areolar connective tissue

Answer 13

▪ Also known as Spongy Connective Tissue.
▪ It is most widely distributed tissue in the body.
▪ Maximum intercellular space and matrix is present.
▪Due to irregular arrangement of bundle of collagen fibres many
gaps are present. These gaps are called areolae.
▪ In areolae other component of connective tissue like fibres, cells
& matrix are distributed. Few elastic fibres are present.
▪ Fibroblast cells, macrophages and mast cell are more in number.
▪ Function: it serve as a support framework for epithelium.

Question 14

where is areolar tissue found

Answer 14

-tela subcutanea: tissue connecting skin and unerlying tissue
- submucosa of trachea,bronchi,oesophagus and stomach,inestine
-endomysium and perimysium of muscle tissue

• joins integument with muscles

Question 15

what is adipose tissue

Answer 15

Another type of loose connective tissue located mainly
beneath the skin.
▪ It contain adipocytes / fat cells abundantly.
▪ The cells of this tissue are specialized to store fats the excess
of nutrients which are not used immediately are converted
into fats and are stored in this tissue.

-fibroplasts store fats in adipose tissue

Question 16

where is brown fat found

Answer 16

Cold resistance in new born baby is due to
presence of brown fat.
Hibernating animals Like Rat, Shrew

Question 17

where is white fat

Answer 17

A thin continuous layer of white fat under the
dermis of skin which is also called hypodermis
of skin.
*Yellow Bone Marrow
*Blubber of whale
*Hump Of Camel
*Fat Bodies of Frog

Question 18

2 types of dense connective tissue

Answer 18

• More fibers and less matrix.
• Fibers and fibroblast cells are compactly
  packed in dense connective tissue .

-dense regular tissue-cord
-dense irregular tissue - sheath

white fibrous
-more of collagen, less elastin

yellow fibrous
-less collagen, more elsatin

Question 19

explain different white fibrous connective tissue

Answer 19

CORD –Many parallel bundles of collagen fibres and rows of
fibroblasts in matrix are present alternately (Regular pattern)
TENDON : Connect muscle to bone

SHEATH – In this form there is no regular pattern of fibres and
fibroblasts in matrix. Cells and fibres are arranged in criss-cross
manner.
Outermost covering of major organs
(1)PERICARDIUM

Question 20

explain different yellow fibrous connective tissue

Answer 20

CORD –In this form bundles of collagen fibres and fibroblasts in matrix
distributed in regular pattern & in matrix yellow fibres form network.
LIGAMENT : Connect bone to bone

SHEATH – Irregular distributions of fibres and matrix with elastic fibre.
Wall of Alveoli of Lungs////Wall of Small Bronchioles
Wall of Lymph Vessels & Blood Vessels
True Vocal Cords

Question 21

describe cartilage

Answer 21

▪Outer most covering of cartilage is called Perichondrium (WFCT).
▪Matrix is solid, pliable and can resists compression.
▪Chondroblast- Cartilage producing cells.
▪Chondrocyte- Enclosed in small cavities (Lacunna).)formed by division of chondroblast)
▪Chondroclast- Cartilage destroying cells.
▪Matrix of cartilage is called chondrin composed of Chondroitin-6-
sulphate and mucopolysacchride (hyaluronic acid).
Matrix of cartilage provides rigidity & elasticity to cartilage.
▪Blood supply is absent in the matrix of cartilage but present in
perichondrium.

Question 22

what are the 4 types of cartilage?

Answer 22

(i hyaline cartilage
(ii)elastic cartilage
(ii) white fibrous cartilage
(iv) calcified cartilage

Question 23

what is hyaline cartilage

Answer 23

It is most common cartilage of human body.
▪Most of the part of embryonic skeleton is composed of this
cartilage so maximum bones of our body are cartilagenous
bones because they are developed from cartilage.
▪Matrix of cartilage is glass like clear because fibres are
completely absent.
▪Colour of matrix is bluish and is translucent.

(2) “C” Shaped Rings of Trachea and Bronchi
(1) Laryngeal Cartilage
(3) Nasal Septum
(4) Sternal Part of Ribs (Costal Cartilage)
(5) Articular Cartilage

Question 24

what is elastic cartilage

Answer 24

In the matrix of this cartilage yellow fibres form network so
is highly flexible cartilage of our body.

1. Tip of nose
2. Ear Pinna
3. Eustachian Tube
4. Epiglottis

Question 25

what is whit fibrous cartilage

Answer 25

Perichondrium is absent because complete WFCT is converted
into cartilage.
In matrix bundle of collagen fibres are more in quantity so it is
the strongest cartilage.

Pubic Symphysis- Connect both the pelvic halves with
each other.
2.Intervertebral Disc

Question 26

what is calcified cartilage

Answer 26

*It is modified hyaline cartilage but due to deposition of
calcium salts its matrix becomes hard like bones (hardest
cartilage) .
*Deposits of Calcium salt
1. Head of femur and humerus.

Question 27

what is
(i) study ofbone?
(ii) process of bone formtion

Answer 27

▪ Study of bone is called Osteology.
▪ Process of bone formation is called ossification.

Question 28

what are the cells of bone

Answer 28

(i) osteoblast- bone producing cells which divide to form osteocyte
(ii) osteocyte- mature cell of bone
Only one osteocyte is found in one lacuna.
Synthesize organic part of matrix.

(iii)Osteoclast :- bone destroying cells

Question 29

what does matrix of bone have

Answer 29

Inorganic part
Calcium phosphate – 80%
Calcium carbonate – 10%
Magnesium phosphate- 10%
Flourides

Organic part
Ossein in which
Bundle of collagen
fibres suspended
in sulphated muco -
polysaccharide.

Question 30

what are two parts of bone

Answer 30

(i) epiphysis- top and bottom end
(ii)diaphysis- middle long part

Question 31

describe epiphysis

Answer 31

Composed of spongy bone.
*Matrix is present in the form of
trabeculae, filled with red bone
marrow which is the site of
production of RBC.

in the diaphysis, there is fatty yellow bone marrow

Question 32

explain the structure of diaphysis

Answer 32

• Concentric layers of matrix which are present around Haversian canal.Between these lamellae layer of osteocyte cells are also present.
  *Osteocyte are present in the lacunae. Each osteocyte is inter
  connected with adjacent osteocyte by their cytoplasmic process.
  *Cytoplasmic process of osteocyte called as canaliculi are present in the minute canals of
  lacunae
• In each lacunae only one osteocyte cell is present.

Question 33

what is haversian canals

Answer 33

Haversian canal :
Longitudinal canals which are arranged parallel to long axis of bone. In these canals one or
two blood capillaries and nerve fibres are present.
Volkmann’s canal :

These are transverse/horizontal or oblique canals. Haversian canals are interconnected by
volkmann’s canal.

Question 34

what are cartilagenous bones

Answer 34

These bones are formed by
the ossification of cartilage.
* In the formation of these
bones two types of cells are
required.
Chondroclast- Which reabsorb
cartilagenous matter.

Osteoblast- Which deposit bony
matter into cartilage so
cartilage is replaced by
bone. Hence these
bones are also called
replacing bones.

Eg.Maximum bones of our
body like limb bones
(Fore limbs & Hind
limbs), Ribs.

Question 35

what are membraneous bones/dermal bones/investingbones

Answer 35

These bones are
formed by ossification
in the connective
tissue of dermis.
Eg. Pubis, Sternum, Nasal
Bone, Clavicle, Scapula,
Jaw bone & flat bones of
skull.

Question 36

what are seasmoid bones

Answer 36

These bones
are developed
by the
ossification of
tendons at the
joints.
*Patella
(knee
cap) - Largest
sesamoid
bone.
*Pisiform
(wrist bone) of
human

Question 37

visceral bones

Answer 37

If ossification takes
place in the visceral
organs then visceral
bones are formed.
In humans these
bones are absent.

Question 38

Haversian canals are

Answer 38

Mammalian feature

Question 39

Name type of cartilage in
i) cartilage of santorini
ii) cricoid

Answer 39

i) it is present in the larynx. Helps produce sound. ELASTIC CARTILAGE

ii) ring shaped structure of present at the base of the larynx it is made up of hyaline cartilage

Question 40

Undifferentiated cells of proper connective tissue

Answer 40

Mesenchymal cells
Mesenchymal cells are like the “master builders” of the body. They can transform into different types of cells, such as bone, cartilage, fat, or muscle cells, depending on what the body needs. They’re important for healing and growing new tissues when there’s damage or growth happening in the body.

Question 41

Endosteum

Answer 41

Endosteum is composed of reticular connective tissue. In anatomy, the endosteum is a thin layer of connective tissue, that lines the surface of the bony tissue, that forms the medullary cavity of long bones.