Structural Organisation in Animals Class 11 Notes Biology Chapter 7

 Page 1


Points to Remember
 Cell junctions—In nearly all animal tissues, specialised junction provide 
structural and functional links between its individual cells.
Three Types of  Cell junctions—
1. Tight junctions : Plasma membranes of adjacent cells are fused at intervals.
They help to stop substances from leaking across a tissue.
2. Adhering junctions : Perform cementing function to keep neighbouring
cells together.
3. Gap junction : Facilitate the cells to communicate with each other by
connecting the cytoplasm of adjoining cells for rapid transfer of ions, small
molecules and soometimes big molecules.
Types of Fundamental Animal Tissues
 S.No.  T ype Location Functions
1. Epithelial Tissues Free Surfaces Protection, Secretion, 
Excretion, absorption,
Sensory and reproduction
2. Connective Tissues Inside body, in organs Holding or binding, support,
other tissues and below transport and circulation,
skin protection and storage.
3. Muscular Tissues Inside movable parts Movements and locomotion
4. Nervous Tissues Central Nervous System Communication and control
& every organ Peripheral
Nervous System.
Page 2


Points to Remember
 Cell junctions—In nearly all animal tissues, specialised junction provide 
structural and functional links between its individual cells.
Three Types of  Cell junctions—
1. Tight junctions : Plasma membranes of adjacent cells are fused at intervals.
They help to stop substances from leaking across a tissue.
2. Adhering junctions : Perform cementing function to keep neighbouring
cells together.
3. Gap junction : Facilitate the cells to communicate with each other by
connecting the cytoplasm of adjoining cells for rapid transfer of ions, small
molecules and soometimes big molecules.
Types of Fundamental Animal Tissues
 S.No.  T ype Location Functions
1. Epithelial Tissues Free Surfaces Protection, Secretion, 
Excretion, absorption,
Sensory and reproduction
2. Connective Tissues Inside body, in organs Holding or binding, support,
other tissues and below transport and circulation,
skin protection and storage.
3. Muscular Tissues Inside movable parts Movements and locomotion
4. Nervous Tissues Central Nervous System Communication and control
& every organ Peripheral
Nervous System.
Animal Tissues
Epithelial Connective Muscular   Neural
Epithelial Tissue
(A)  Simple : ? Composed of single layer of cells.
? Functions as lining for body cavities, ducts and tubes.
1. Squamous ? single	thin	layer	of	flattened 	cells.
? found in walls of blood vessels, air sacs of lungs.
2. Cuboidal ? single layer of cube like cells.
? found in ducts of glands and tubular parts of nephron.
3. Columnar ? single layer of tall and slender cells.
? free surface may have microvilli.
? found in lining of stomach and intestine
4. Ciliated ? columnar or cubolidal cells with cilia.
? move	 particles	 or	 mucus	 in	 specific 	 direction,	 in
bronchioles, fallopian tubes.
(B) Compound :
? Made of more than one layer of cells.
? Provide protection against chemical and mechanical stresses.
? Cover dry surface of skin, moist cavity, pharynx, inner lining of ducts of
salivary glands and pancreatic ducts.
Glandular epithelium
          Exocrine glands           Endocrine glands
? secrete mucus, saliva,oil, milk ? secrete hormones.
digestive enzymes
? products released through ducts. ? secrete	directly 	into 	the	fluid
bathing the gland.
Page 3


Points to Remember
 Cell junctions—In nearly all animal tissues, specialised junction provide 
structural and functional links between its individual cells.
Three Types of  Cell junctions—
1. Tight junctions : Plasma membranes of adjacent cells are fused at intervals.
They help to stop substances from leaking across a tissue.
2. Adhering junctions : Perform cementing function to keep neighbouring
cells together.
3. Gap junction : Facilitate the cells to communicate with each other by
connecting the cytoplasm of adjoining cells for rapid transfer of ions, small
molecules and soometimes big molecules.
Types of Fundamental Animal Tissues
 S.No.  T ype Location Functions
1. Epithelial Tissues Free Surfaces Protection, Secretion, 
Excretion, absorption,
Sensory and reproduction
2. Connective Tissues Inside body, in organs Holding or binding, support,
other tissues and below transport and circulation,
skin protection and storage.
3. Muscular Tissues Inside movable parts Movements and locomotion
4. Nervous Tissues Central Nervous System Communication and control
& every organ Peripheral
Nervous System.
Animal Tissues
Epithelial Connective Muscular   Neural
Epithelial Tissue
(A)  Simple : ? Composed of single layer of cells.
? Functions as lining for body cavities, ducts and tubes.
1. Squamous ? single	thin	layer	of	flattened 	cells.
? found in walls of blood vessels, air sacs of lungs.
2. Cuboidal ? single layer of cube like cells.
? found in ducts of glands and tubular parts of nephron.
3. Columnar ? single layer of tall and slender cells.
? free surface may have microvilli.
? found in lining of stomach and intestine
4. Ciliated ? columnar or cubolidal cells with cilia.
? move	 particles	 or	 mucus	 in	 specific 	 direction,	 in
bronchioles, fallopian tubes.
(B) Compound :
? Made of more than one layer of cells.
? Provide protection against chemical and mechanical stresses.
? Cover dry surface of skin, moist cavity, pharynx, inner lining of ducts of
salivary glands and pancreatic ducts.
Glandular epithelium
          Exocrine glands           Endocrine glands
? secrete mucus, saliva,oil, milk ? secrete hormones.
digestive enzymes
? products released through ducts. ? secrete	directly 	into 	the	fluid
bathing the gland.
 Connective tissue : Link and support other tissues/organs of the body.
Connective Tissues
 Proper Connective Tissues Specialised Connective Tissues
Loose connective          Dense connective           Skeletal Fluid Connective
       Tissues Tissues Tissues                Tissues
Areolar    Adipose   Dense          Dense      Bone      Cartilage      Blood        Lymph
regular          irregular 
             eg. Tendon  
ligament 
Loose Connective Tissue
  (has cells and fibres loosely arranged in semi-fluid ground substance)
(i) Areolar Tissue :
 ? present beneath the skin.
? contains fibroblasts, macrophages and mast cells.
 ? serves as a support framework for epithelium
(ii) Adipose Tissue :
 ? located beneath the skin.
 ? cells are specialised to store fats.
Dense Connective Tissue
  Fibres and fibroblasts are compactly packed.
(i) Dense Regular
 ? Collagen fibres present in rows.
 ? Tendons attach skeletal muscle to bone.
 ? Ligaments attach bone to bone.
(ii) Dense Irregular
 ? Has collagen fibres and fibroblasts oriented differently.
 ? This tissue is present in the skin.
Specialised Connective Tissues
(i) Cartilage : made up of chondrocytes and collagen fibres; inter cellular 
material is solid and resists compression. Present in tip of nose outer ear 
joints, etc.
Page 4


Points to Remember
 Cell junctions—In nearly all animal tissues, specialised junction provide 
structural and functional links between its individual cells.
Three Types of  Cell junctions—
1. Tight junctions : Plasma membranes of adjacent cells are fused at intervals.
They help to stop substances from leaking across a tissue.
2. Adhering junctions : Perform cementing function to keep neighbouring
cells together.
3. Gap junction : Facilitate the cells to communicate with each other by
connecting the cytoplasm of adjoining cells for rapid transfer of ions, small
molecules and soometimes big molecules.
Types of Fundamental Animal Tissues
 S.No.  T ype Location Functions
1. Epithelial Tissues Free Surfaces Protection, Secretion, 
Excretion, absorption,
Sensory and reproduction
2. Connective Tissues Inside body, in organs Holding or binding, support,
other tissues and below transport and circulation,
skin protection and storage.
3. Muscular Tissues Inside movable parts Movements and locomotion
4. Nervous Tissues Central Nervous System Communication and control
& every organ Peripheral
Nervous System.
Animal Tissues
Epithelial Connective Muscular   Neural
Epithelial Tissue
(A)  Simple : ? Composed of single layer of cells.
? Functions as lining for body cavities, ducts and tubes.
1. Squamous ? single	thin	layer	of	flattened 	cells.
? found in walls of blood vessels, air sacs of lungs.
2. Cuboidal ? single layer of cube like cells.
? found in ducts of glands and tubular parts of nephron.
3. Columnar ? single layer of tall and slender cells.
? free surface may have microvilli.
? found in lining of stomach and intestine
4. Ciliated ? columnar or cubolidal cells with cilia.
? move	 particles	 or	 mucus	 in	 specific 	 direction,	 in
bronchioles, fallopian tubes.
(B) Compound :
? Made of more than one layer of cells.
? Provide protection against chemical and mechanical stresses.
? Cover dry surface of skin, moist cavity, pharynx, inner lining of ducts of
salivary glands and pancreatic ducts.
Glandular epithelium
          Exocrine glands           Endocrine glands
? secrete mucus, saliva,oil, milk ? secrete hormones.
digestive enzymes
? products released through ducts. ? secrete	directly 	into 	the	fluid
bathing the gland.
 Connective tissue : Link and support other tissues/organs of the body.
Connective Tissues
 Proper Connective Tissues Specialised Connective Tissues
Loose connective          Dense connective           Skeletal Fluid Connective
       Tissues Tissues Tissues                Tissues
Areolar    Adipose   Dense          Dense      Bone      Cartilage      Blood        Lymph
regular          irregular 
             eg. Tendon  
ligament 
Loose Connective Tissue
  (has cells and fibres loosely arranged in semi-fluid ground substance)
(i) Areolar Tissue :
 ? present beneath the skin.
? contains fibroblasts, macrophages and mast cells.
 ? serves as a support framework for epithelium
(ii) Adipose Tissue :
 ? located beneath the skin.
 ? cells are specialised to store fats.
Dense Connective Tissue
  Fibres and fibroblasts are compactly packed.
(i) Dense Regular
 ? Collagen fibres present in rows.
 ? Tendons attach skeletal muscle to bone.
 ? Ligaments attach bone to bone.
(ii) Dense Irregular
 ? Has collagen fibres and fibroblasts oriented differently.
 ? This tissue is present in the skin.
Specialised Connective Tissues
(i) Cartilage : made up of chondrocytes and collagen fibres; inter cellular 
material is solid and resists compression. Present in tip of nose outer ear 
joints, etc.
76
MUSCULAR TISSUES 
(long, contractile cells called fibres, bring about movement and locomotion)
 Skeletal Muscle  Smooth Muscle  Cordiac Muscle
? Striated ? Non-striated ? Striated with intercalated
disc for communication
? Closely attached to ? Forms wall of ? Occurs in heart wall
sekeletal bones. ? Internal Organs ? Short cyclindrical
like	blood	vessels										uninucleated 	fibres
stomach, intestine
? long cylindrical ? Spindle like
multinucleated 	fibres	 uninucleated 	 fibres.
(ii) Bones : 	 G round	 s ubs tance 	 is 	 rich	 in	 calcium	 s alts 	 and 	 collagen 	 fibres 	 O steocyt	
es are present in launae. Bones support and protect softer tissues and organs. 
They interact with skeletal muscles to bring about movements. Bone marrow 
in some bones is the site of blood cell formation.
 (iii) Blood : Fluid coonective tissue, consists of plasma and blood cells.
Vascular Tissues
              Blood Lymph
    Plasma Formed Plasma             Leucocytes
Elements
Blood Corpuscles Blood Platelets
  Erythrocytes Leucocytes
								(RBCs) (WBC)
Granulocytes Agranulocytes
Neutrophils       Eosinophils          Basophils             Monocytes          Lymphocytes
Page 5


Points to Remember
 Cell junctions—In nearly all animal tissues, specialised junction provide 
structural and functional links between its individual cells.
Three Types of  Cell junctions—
1. Tight junctions : Plasma membranes of adjacent cells are fused at intervals.
They help to stop substances from leaking across a tissue.
2. Adhering junctions : Perform cementing function to keep neighbouring
cells together.
3. Gap junction : Facilitate the cells to communicate with each other by
connecting the cytoplasm of adjoining cells for rapid transfer of ions, small
molecules and soometimes big molecules.
Types of Fundamental Animal Tissues
 S.No.  T ype Location Functions
1. Epithelial Tissues Free Surfaces Protection, Secretion, 
Excretion, absorption,
Sensory and reproduction
2. Connective Tissues Inside body, in organs Holding or binding, support,
other tissues and below transport and circulation,
skin protection and storage.
3. Muscular Tissues Inside movable parts Movements and locomotion
4. Nervous Tissues Central Nervous System Communication and control
& every organ Peripheral
Nervous System.
Animal Tissues
Epithelial Connective Muscular   Neural
Epithelial Tissue
(A)  Simple : ? Composed of single layer of cells.
? Functions as lining for body cavities, ducts and tubes.
1. Squamous ? single	thin	layer	of	flattened 	cells.
? found in walls of blood vessels, air sacs of lungs.
2. Cuboidal ? single layer of cube like cells.
? found in ducts of glands and tubular parts of nephron.
3. Columnar ? single layer of tall and slender cells.
? free surface may have microvilli.
? found in lining of stomach and intestine
4. Ciliated ? columnar or cubolidal cells with cilia.
? move	 particles	 or	 mucus	 in	 specific 	 direction,	 in
bronchioles, fallopian tubes.
(B) Compound :
? Made of more than one layer of cells.
? Provide protection against chemical and mechanical stresses.
? Cover dry surface of skin, moist cavity, pharynx, inner lining of ducts of
salivary glands and pancreatic ducts.
Glandular epithelium
          Exocrine glands           Endocrine glands
? secrete mucus, saliva,oil, milk ? secrete hormones.
digestive enzymes
? products released through ducts. ? secrete	directly 	into 	the	fluid
bathing the gland.
 Connective tissue : Link and support other tissues/organs of the body.
Connective Tissues
 Proper Connective Tissues Specialised Connective Tissues
Loose connective          Dense connective           Skeletal Fluid Connective
       Tissues Tissues Tissues                Tissues
Areolar    Adipose   Dense          Dense      Bone      Cartilage      Blood        Lymph
regular          irregular 
             eg. Tendon  
ligament 
Loose Connective Tissue
  (has cells and fibres loosely arranged in semi-fluid ground substance)
(i) Areolar Tissue :
 ? present beneath the skin.
? contains fibroblasts, macrophages and mast cells.
 ? serves as a support framework for epithelium
(ii) Adipose Tissue :
 ? located beneath the skin.
 ? cells are specialised to store fats.
Dense Connective Tissue
  Fibres and fibroblasts are compactly packed.
(i) Dense Regular
 ? Collagen fibres present in rows.
 ? Tendons attach skeletal muscle to bone.
 ? Ligaments attach bone to bone.
(ii) Dense Irregular
 ? Has collagen fibres and fibroblasts oriented differently.
 ? This tissue is present in the skin.
Specialised Connective Tissues
(i) Cartilage : made up of chondrocytes and collagen fibres; inter cellular 
material is solid and resists compression. Present in tip of nose outer ear 
joints, etc.
76
MUSCULAR TISSUES 
(long, contractile cells called fibres, bring about movement and locomotion)
 Skeletal Muscle  Smooth Muscle  Cordiac Muscle
? Striated ? Non-striated ? Striated with intercalated
disc for communication
? Closely attached to ? Forms wall of ? Occurs in heart wall
sekeletal bones. ? Internal Organs ? Short cyclindrical
like	blood	vessels										uninucleated 	fibres
stomach, intestine
? long cylindrical ? Spindle like
multinucleated 	fibres	 uninucleated 	 fibres.
(ii) Bones : 	 G round	 s ubs tance 	 is 	 rich	 in	 calcium	 s alts 	 and 	 collagen 	 fibres 	 O steocyt	
es are present in launae. Bones support and protect softer tissues and organs. 
They interact with skeletal muscles to bring about movements. Bone marrow 
in some bones is the site of blood cell formation.
 (iii) Blood : Fluid coonective tissue, consists of plasma and blood cells.
Vascular Tissues
              Blood Lymph
    Plasma Formed Plasma             Leucocytes
Elements
Blood Corpuscles Blood Platelets
  Erythrocytes Leucocytes
								(RBCs) (WBC)
Granulocytes Agranulocytes
Neutrophils       Eosinophils          Basophils             Monocytes          Lymphocytes
77
Neural Tissues
? Neurons are the functional unit and are excitable cells.
? Neurogila cells make up more than half the volume of neural tissue.
They protect and support neurons.
Cockroach— Periplaneta americana (Phylum-Arthropoda, 	 Class-Insecta)
Habitat : Cockroach is a terrestrial, nocturnal, ominivorous,unisexual, 
oviparous insect. Body convered by a chitinous, hard exoskeleton of hard plates 
called sclerities.
Morphology :
Head : Triangular, formed by fusion of 6 segments. Bears a pair of antennae, 
compound	 eyes.	 Mouth	 parts 	 consists	 of	 labrum 	 (upper 	 lip),	 a	 pair 	 of	 mandibles,	
a	pair	of	maxillae,labium 	(lower	lip), 	hypharynx	(acts	as 	tongue).
Thorax : 3	segments; 	prothorax,	measothorax	and	metathorax.
Bears 2 pairs of wings :
Forewings 	:	tegmina 	(mesothoracic).
Hindwings	:	transparent,	membranous 	(metathoracic)
3	pairs 	of 	legs	in	thoracic 	segments.	(one 	pair	in	each 	thoracic	segment.)
Abdomen : 10 segments. Bears a pair of long, segmented  anal cerci in 
both sexes and a pair of short, unjoined anal styles in males only 7th segment is 
boat shaped.
Also has anus and genital aperture at the hind end. Genital aperture 
surrouonded by external genitalia called gonapophysis or phallomere.
           Male Cockroach             Female Cockroach
1. Abdomen long and narrow 1. Abdomen short and broad
2. All nine sterna visible 2. Seven sterna visible. (7th sternum
fused	with	8th	and	9th	sterna)
3. Anal style present 3. Anal style absent
Anatomy : Study of the morphology of internal organs.
Alimentary canal : Divided into foregut, midgut and hindgut.
Mouth ? Pharynx ? Oesophagus ? 	 Crop 	 (s tores	 food) 	 ? Gizzard (grinding
of	 food)	 ? Hepatic caecae (at juncti on	 of	 fore	 and	 midgut;	 secretes	 digestive	
juice) 	 ?	Hindgut	(ileum,	colon,	rectum) 	 ? Anus.