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TUTORIAL LABORATORY 1MULTICELLULAR ORGANIZATION OF ANIMALS

• Levels of organizationcells --> tissues --> organs --> organ systems

• Histology– the study of tissues.

• Tissue– group of similar cells performing a common activity

• Organ– group of tissues collectively performing a specific function

• Organ system– group of organs performing a major body function

ANIMAL TISSUES

• Four basic animal tissue types with respect to their structure, location, and function

1) epithelial tissue2) connective tissue3) muscle tissue 4) nervous tissue

EPITHELIAL TISSUE

• the covering or lining of free body surfaces, both internal and external

• Functions: – protection (as on the surface of skin and in the lining of many internal organs)– absorption of nutrients (as in intestines)– secretion (as in kidneys, salivary glands, intestines, thyroid gland), – lubrication(as in areas where mucus production occurs), and exchange of

materials by diffusion (as in lungs and blood capillaries) – barrier against mechanical injury, pathogens, and fluid loss

Classification of Epithelial Tissue• epithelial tissue are tightly packed and rest on a thin basement membrane• apical or luminal surface = free surface of the tissue is exposed to air (as in skin) or

fluid (as in stomach)• cilia, microvilli and stereocilia are located on this surface.• classified according to the shape of the cells at the outermost layer and the

arrangement of the cells into one or more layers.i) squamous -- flat, scale-like cells (“fried-egg” appearance).ii) cuboidal -- cells appear square in side view with nucleus in a central position.iii) columnar -- cells appear rectangular in side view withthe nucleus displaced toward the base of the cell.

• How do epithelial tissue appear?• one single layer = _____?• two or more layers =_____?

EPITHELIAL TISSUE

• one single layer = simple• two or more layers = stratified

EPITHELIAL TISSUE

Hint: One layer epithelium and the Different multilayer epithelial.• 1• 2• 3• 4• 5• 6

List the 6 types of EPITHELIAL TISSUE

1. Simple Squamous Epithelium2. Simple Cuboidal Epithelium3. Simple Columnar Epithelium4. Non-Keratinized Stratified Squamous Epithelium5. Keratinized Stratified Squamous Epithelium6. Pseudostratified ciliated columnar epithelium

EPITHELIAL TISSUE

1. Identify the Epithelium.

• List the possible location and its function.

1. Simple Squamous Epithelium

• single row of flat cells• resemble fried eggs, with a bulging oval nucleus• Location:

– Kidneys around glomeruli (singular, glomerulus)– it lines internal surfaces of the ventral body cavities, blood vessels, lymphatic

vessels, and heart – it forms the entire wall of capillaries – forms the walls of the alveoli of the lungs

• Function: exchange of materials by diffusion (as in lungs and blood capillaries)

Name, Location and Function?

1. Simple Squamous Epithelium

Name, Function and Location?What is Difference in location of this type of cell and function compare d to simple squamous epithelium?Hint: They can be found in the same organ but one of the two can only be found in another organ.

2. Simple Cuboidal Epithelium

• appears as a single row of cube-shaped cells• Location: kidney’s nephrons tubules• Function: secretion and absorption• Simple squamous= gas exchange, glomerli of

kidney.

Identify which type of cell exist in both places.

Simple squamous in the GlomerulusSimple cuboidal in the Nephron tubules

Identify the type of cell, location,fuction

Kidney

Name, Location, Function• Identify A,B,C• What is the purpose of microvilli and the function of A

3. Simple Columnar Epithelium• Single layer of tall, column-shaped cells with oblong nuclei• Location: walls of villi in small intestine• Function: absorption of nutrients, secretion of digestive juices as well as

secretion of mucus by goblet cells – Goblet produce mucus to lubricate varies tissues– known respectively as villi and crypts

• The apical surface microvilli = increase the surface area for absorption of nutrients

Name, Location and fuction?

3. Simple Columnar Epithelium

Name, Location, Fucntion?

3. Simple Columnar Epithelium

Simple Columnar epithelium

stratified squamous epithelium

• What are the two type of stratified squamous epithelium?

stratified squamous epithelium

• There are two types of stratified squamous epithelium: – non-keratinized (also known as wet)– keratinized (also known as dry)

What is the function of stratified squamous Epithelium? Hint: also aids in health.What are the location and what are they subjected to?

4. Non-Keratinized Stratified Squamous Epithelium

• composed of several to many layers of cells• Location: – in places subjected to abrasion– moist areas of the body, on surfaces that are

subjected to abrasion, such as oral cavity, pharynx, esophagus, vagina, and anus

• Function: – protection against abrasion and pathogens to

underlying tissues.



• Identify A,B, and C.

• Explain the process in which cells are replenished and what type of cells are in the “deepest” layer close to the basement membrane?

• Explain the significance of the movement of these cells and its significance. What does this process ensure to


• the deeper layer (close to the basement membrane) of the stratified squamous epithelium is composed of cuboidal cells that are actively dividing by mitosis to produce new cells.

• Newly produced cells are pushed upward toward the surface of the tissue and are gradually transformed into flat, squamous cells.

• These cells are continually sloughed off. Thus, the organization of the stratified squamous epithelium ensures that abrasion affects the oldest (outermost) cells, while protecting the underlying tissues.


Name, location, and function.Be specific with the name. there are two types of this epithelium

Identify which type of epithelium would be at each ends of the double arrow. Which is young and which side is old.


Left is cuboidal shaped and young.Right squamous shaped old and inactive.

In what location of the body are you most likely to find this cell. Hint they are subjected to ….?Describe how the very top layer establishes a waterproof and microbe-proof barrier.Describe the reason why “Thick” keratinized epithelium and “thin” keratinized epithelium are found in different locations.

keratinized stratified epithelium.

• Location: found on dry surfaces, such as the surface of skin. Specifically, it composes the most superficial layer skin, known as epidermis.

• As the epithelial cells produced at the base get pushed to the surface, they die and undergo changes, including accumulation of the protein, known as keratin.

• Function: These dead (or cornified) cells infused with keratin provide a waterproof and microbe-proof barrier

• There are two types of keratinized epithelium: thick and thin.– The thick one is found on the surface of the soles of your feet and on the

surface of the palms of your hands since these areas are exposed to abrasion and require a thick layer of keratin for protection.

– The thin one is found everywhere else on the surface of the skin of your body

5. Keratinized Stratified Squamous Epithelium

Identify.

5. Keratinized Stratified Squamous Epithelium

Pseudostratified Ciliated Columnar Epithelium

Identify the location of this EpitheliumWhat is the function of this cell in these specific locations?Explain why this epithelium is called “Pseudostratified”.what types of shapes does it consist of and what does this mean overall about the cells?

6. Pseudostratified Ciliated Columnar Epithelium

• Location: lines the nasal cavity, trachea, and bronchi• Function: to protect these structures, secrete mucus

by goblet cells, and move mucus by cilia.• This type of epithelium consists of a single row of

cells. Most of these cells have a columnar shape, while other, shorter cells, are more cuboidal. The term “pseudostratified” literally means “falsely stratified”.

• In other words, the epithelium looks as if it has multiple layers but it only has one layer. This is due to the fact that the cells are of differing heights.

Identify the name epithelium, ABC and D. What is the fucntion of A and C?what is the function of mucus?

• Goblet cells– oval cells scattered throughout this epithelium– secrete mucus into the respiratory tree.– function of mucus is to trap foreign material


Identify the blank space.

Identify the epithelium and A & B and its function.

CONNECTIVE TISSUE

• The most widespread and abundant type of tissue in the human body.

• Function: primarily to support, anchor and connect various parts of the body.

• All types have three basic structural elements: cells, fibres and intercellular substance (ground substance).

• Both fibres and ground substance make up the extracellular matrix.

• Connective Tissue Proper– encompasses all organs and body cavities connecting

one part with another and, equally important, separating one group of cells from another. • areolar (loose) tissue• adipose tissue(fat)

• Specialized Connective Tissues• cartilage• bone• blood

Connective Tissue

• The most common cell types are:– fibroblasts, which produce fibres and other intercellular

materials. – The two most common types of fibres are:

• collagen (collagenous) = strength• elastic = elasticity

• Both the cells and the fibres are embedded in the intercellular substance (ground substance).

• The consistency of this substance is highly variable from liquid to gelatin-like to a much more rigid material.

Connective Tissue

What is the location and function of Areolar connective tissue? Hint this is also why it is the most “widespread” connective tissue.This connective tissue is called areolar “loose” connective tissue what part of its structure contributes to this name. Identify the color and appears of Collagen fibres, Elastic fibres, and mast cells.

Areolar (Loose) Connective Tissue

• the most widespread connective tissue of the body.• Location/Function:

– To attach the skin to the underlying tissue.– It also fills the spaces between various organs and thus holds them in

place as well as cushions and protects them.– It also surrounds and supports the blood vessels.

• The fibres of areolar connective tissue are arranged in no particular pattern but run in all directions and form a loose network in the intercellular material.

• Collagen fibres = predominant, appear as broad pink bands • Elastic fibres = appear as thin, dark fibres are also present• Mast cells = dark-staining granules in their cytoplasm

1. Areolar (Loose) Connective Tissue

Identify AB and C

1. Areolar (Loose) Connective Tissue

• What is one definite physical characteristic of adipose connective tissue? It has ..?

• As a result of the above answer where is the location of the nucleus.

• What is the location and function of adipose tissue?

Adipose Connective Tissue

• Characterized by a large internal fat droplet.• The nucleus is displaced to the edge of the cell.• When they accumulate in large numbers, they

become the predominant cell type and form adipose (fat) tissue.

• Location/Function: storage site for fats (lipids), also pads and protects certain organs and regions of the body. As well, it forms an insulating layer under the skin which helps regulate body temperature

2. Adipose Connective Tissue

2. Adipose Connective Tissue

Is cartilage a vascular tissue or non-vascular tissue?What are the 3 characteristics of Hyaline cartilage?What is the primary skeletal structure of a fetus?Where in the human body does Hyaline cartilage?Illustrate the function of Hyaline cartilage?

Cartilage: Hyaline cartilage

• Cartilage is a non-vascular tissue• Pliable, compact type of connective tissue. • Characterized by three traits:

– lacunae– chondrocytes,– rigid matrix

• The matrix is a firm gel material that contains fibres and ground substance.• There are three basic types of cartilage in the human body:

– hyaline cartilage, elastic cartilage and fibrocartilage. In this• Location:

– of the skeleton of the mammalian fetus is composed of hyaline cartilage. As the fetus grows, the cartilage is gradually replaced by more supportive bone.

– nasal septum, rings of trachea and bronchi, ends of the ribs (costal cartilage), and the articulating surfaces of most joints

• Function: – provide strong yet flexible support and to reduce friction within joints.– structural reinforcement.

3. Cartilage: Hyaline cartilage

Locate the Chondrocyte , Lacuna and matrix?What are the chondrocyte trapped in?

Identify this epithelium

• Chondrocytes– the large cartilage cells, which are trapped within

the matrix in spaces called lacunae


Blood

• What are the three components that make up blood? Which of the three are most abundant and are responsible for the transport of oxygen, carbon dioxide and nutrients.

4. Blood

• liquid extracellular matrix called plasma, which contains water, salts, proteins, glucose, lipids, glycoproteins, hormones, amino acids, and vitamins. – Erythrocytes (red blood cells)– Leucocytes (white bloodcells) – Thrombocytes or Platelets

• Erythrocytes are the most abundant blood cells and are responsible for transport of oxygen, some carbon dioxide, and nutrients.

• Note that most carbon dioxide, though, is carried byplasma.

A. Erythrocytes

• Using the correct term illustrate the structure of Erythrocytes that increases its efficiency transport of oxygen?

• What is extremely special from this cell and other “organelle” cells?

• What is the approximate life span of Erythrocytes?

• Where are erythrocytes destroyed via macrophages.

B. Leukocytes(white bloodcel)

• What are some of the difference of erythrocytes and Leukocytes? Where does it usually reside in the blood or outside of the blood in other tissues?

• What is the function of Leukocytes?

B. Leukocytes

• larger, nucleated, and although found in the blood during transport, they usually function outside of blood, in other tissues

• Function: defence of the organism against bacteria, parasites, and pathogenic microorganisms, such as viruses, fungi and protists.

C. Platelets

• Define the simple structure of platelet and what is its significant function how does its size assists in its function?

C. Platelets

• Small cell fragments, which aid in blood clotting• Function: – is to stop the loss of blood from wounds– this purpose, they aggregate and release

factors which promote the blood coagulation.

4. Blood

Muscle Tissue

• 3 types of muscle tissue are distinguished on the basis of structural, functional

• and locational differences:1. Skeletal2. Smooth3. Cardiac

• Muscle cells are highly specialized for contractions. – Such contractions may result in the movement of the

whole body or a portion of it, if the muscles are attached to a movable part of the skeleton.

• Several specific terms are used exclusively for muscle tissue. For example, muscle

• Cells = fibres• Cytoplasm = sarcoplasm• Cell membrane = sarcolemma

Muscle Tissue

• movement of the bones of the skeleton. – For example, the biceps brachii and pectoralis are skeletal muscles.

• Voluntary muscles = As the contraction of the skeletal muscles is under conscious control

• highly modified, giant, multi-nucleate cell (fibre).• Each fibre = cylindrical in shape with blunt, rounded ends. • The flattened nuclei and periphery of the cell, just inside the

sarcolemma. • The "cross-striped" (or striated) appearance of light and dark banding

results from the arrangement of myofibrils, small protein contractile units embedded in the sarcoplasm

• Note the position of the nuclei and the prominent, regular cross-striations

1. Skeletal Muscle Tissue

1. Skeletal Muscle Tissue

• throughout the internal organs of the body especially in regions such as the digestive tract.

• involuntary muscle= contraction is not under conscious nervous control

• shorter in length and they do not exhibit striations (individual fibres)

• within organs or as groups of fibres closely interlaced in sheets or bands.

• lack of cross-striations is usually apparent• central location of the nucleus• Note the characteristic spindle cell shape, the absence of cross-

striations and the prominent nucleus.

2. Smooth Muscle Tissue

2. Smooth Muscle Tissue

• Location: in the wall of a hollow organ, its contractions may cause the contents of the organ to move, e.g. peristaltic movement of material through the digestive tract.

3. Cardiac Muscle Tissue

• highly specialized tissue restricted to the wall of the heart• involuntary type of muscle = contraction is not consciously

controlled.• cardiac fibres tend to form long chains of cells which branch

and intertwine. • This arrangement results in the peculiar "wringing" action of

the heart.• intercalated disc = heavy dark line running across the fibre.• cylindrical shape with one centrally-located, oval nucleus.• Cross-striations are apparent but they are not as regular nor

as prominent as those of skeletal muscle

3. Cardiac Muscle Tissue

Nervous Tissue

There are two divisions of the nervous system:1) The central nervous system = brain and spinal cord2) The peripheral nervous system = all nervous tissue outside the brain and spinal cord • The components of nervous tissue are specialized for

the conduction of electrical• impulses, which allow communication among other

tissue types• The major structural and functional "unit" of nervous

tissue is the nerve cell called neuron

Neurons

• Each neuron is composed of a – cell body containing a nucleus and one or more

long cytoplasmic extensions known as fibres. • Highly branched fibres, called dendrites, bring

impulses toward the cell body, • while a single, unbranched fibre, the axon,

carries information away from the cell body • The overall length of a neuron, including

dendrites, cell body and axon.

Nervous Tissue

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