The process of cellular differentiation

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Task 4

(M2) - Unit 1.2

1) Cell differentiation is the process that takes place inside an embryo that determines which genes are expressed and hence, what type of cell it will resort. This means that the cell can perform a specific function. There are more than 250 general types of cells in the human body.

In plants and animals similar cells are grouped together to form tissues. The human body is made up of many different kind of tissues. The different types of cells that make up the tissues of the human body have distinctive architecture that are well suited for what they do. For example, the cells that forms the epidermis, the thin outer part of the skin, contains several layers of cells that fit closely together. They provide an effective barrier against bacteria and other things that could harm the body. The top layer consists of dead cells are the constantly rubbed off and replaced with cells from below. Thus, cell differentiation is important for the formation of different kind of tissues that provide various kinds of activities and processes which in turn helps the human body to function properly.

3) Liver Tissues – the two cell components found in this tissue are the mitochondria and, the endoplasmic reticulum.

  • Mitochondria – the Liver tissue has a vast abundance of mitochondria present. This is because the liver is the largest internal body organ and mitochondria, being the powerhouse of the cell, provide the liver with the energy for the metabolic regulation so that the liver works more efficiently. It also helps the liver perform various chemical reaction such as the conversion of ammonia into urea and even the release of hormones such as insulin, and glycogen.
  • The endoplasmic reticulum – There are two kinds of endoplasmic reticulum; the rough ER and the smooth ER.

The Rough ER contains several millions of ribosomes and are hence, involved with the production and transportation of proteins.

The Smooth ER helps with the manufacture of lipids and metabolism.

Nervous Tissue – The two cell components found in this tissue are the Axon and the Myelin Sheath.

  • Axon – It is the part of the neuron which is a slender projection. This axon carries the electrical impulses sent from the neurons to the target cells.
  • Myelin Sheath – It is an electrically conducting material found at the axon of a neuron. The myelin sheath helps speed up the impulse travelling through one axon to another and also provides insulation between them.

Muscle Tissue – The two cell components in a muscle tissue are the sacromeme and the actin.

  • Sacromere – It is the the contractile unit of a skeletal and cardic muscle ( stratified muscle). They are protein filaments and repeated pattern of the sacromere results from the arrangements within the myofibrils of two major proteins; actin and myosin. Actin is fiberous protein attached to the Z bands that are protein plates at each end of the sacromere. I – band is the region of the sacromere that contains only filaments of actin. The A band results from the overlapping filaments of actin and myosin. The H-Zone represents the presense of only myosin.
  • Muscle Filaments – A muscle filament consists of actin, myosin, tropomyosin and troponin. A-Band contains a set of thick filaments formed off the contractile protein myosin. The second set of thin filaments overlaps the long filaments in A-Band. The second set of filaments extends partly in I-Band and A-Band. These filaments are formed off a substance called Actin. (eASYtIPS4YOU, 2012)

Epithelial Tissue – The two main components of a epithelial tissue are Villi and Epithelial Membrane.

  • Villi – Each villas contains a network of blood vessles and a small lymphatic vessel known as the lacteal. Some products of digestion such as amino acids and glucose pass into the blood vessels and then into the hypahtic portal vein which carries them to the liver. Most fatty acids and glysorol are recombined to become fats in the intestinal lining and are absorbed into the lacteals. The fluids of the Lacteals passes into the lymphatic vessels and is taken away into the blood stream. (izzo, 2007)
  • Epithelial Membrane - An epithelial membrane consists of a continuous sheet of cells, one or more layers thick, which is attached to the underlying connective tissue by a basement membrane. The cells are joined together at specialized regions called cell junctions. An important point to remember is that epithelia do not contain blood vessels. Nutrients and oxygen reach epithelial membranes by diffusing from blood vessels located in the connective tissue beneath the basement membrane. (IUPUI, n.d.)

Task 5

(D2) - Unit 1.2




They are formed from the neurons in the hypothalamus.

They are formed from the skin tissues located in the roof of the mouth.

It serves as an endocrine gland which secretes hormones.

Functions as a repository for hormones.

It regulates physiological processes related to growth, metabolism.

It releases ACTH which stimulates the production of glucocorticoids to respond to stress reactions or fear.

It is controlled by blood borne release factors.

Controlled by the nerve signals.

Similarities – Both the Anterior and Posterior Pituitary glands are located at the lower part of the brain and secretes hormones which in turn are able to control other glands. The Pituitary gland as a whole is known as the master gland.




Controlled by the somatic nervous system.

They are controlled involuntarily.

These muscles are attached to bones by tendons.

They are located in the heart.

They are cylindrical in shape.

They are semi-spindle in shape.

Contractions are dependent of one another.

Independent contractions.

They have numerous nucleus.

Maximum of two nuclei.

Similarities – Both the cardiac and the skeletal muscle are labelled as striated muscles, which means they have repeating sarcomeres.




Ductless glands.

They have ducts while some may not.

Secretion goes to the blood.

Secreted into the external environment though skin or other sites.

They secrete hormones.

They secrete enzymes.

Example: Pineal gland, Pancreas.

Example: Sweat glands, Gastric gland.

Similarities – both these glands share the same organs like pancreas, kidneys, and testes since they produce both endocrine and exocrine wastes. They are also, primarily comprised of epithelial tissue.

Task 6

(P2) - Unit 1.2, (M1) – Unit 11.1

a) Epithelial Tissue – These tissues have no intercellular spaces because they act as boundaries to keep the different body systems separate. They have two surfaces: one surface is free and the other is the basal surface which is attached to a basement membrane.

Connective Tissue – In these kinds of tissues the cells that are forming are widely spaced and the intercellular spaces are filled with dense fluid-like structure called Intercellular matrix.

Nerve Tissue – the cells of the nervous tissue are called nerve cells or neurons. Neurons contains a cell body (Nucleus, cytoplasm, cell organelles), Dendrites, which are short thin hair-like structures arising from the cytoplasm and help in communication between the neurons, and an axon, which is a single long thin structure arising from the cytoplasm.

Muscle Tissue – They contain muscle fibres and these muscle fibres contains contractile proteins; which enables the contraction and relaxation. They are different kinds of muscle tissues.

  • Skeletal Muscle Tissues – They have long and cylindrical muscle fibres and multinucleated cells and multiple mitochondria to meet energy needs. They are voluntary and striated muscles.
  • Smooth Muscle Tissues – They are spindle shaped cells and are uninucleated cells. They are involuntary and non-striated muscles.
  • Cardiac Muscle Tissues –They muscles have striations that can been seen but are not so prominent and are uninucleated cells. They are also involuntary muscles.







They line every single organ, skin, line the tract.

They are located between other tissues and the liver, bone marrow, cartilages,

Located in the brain and spinal cord and the nerves.

Located in the body, usually around the bones.


They are closely packed cells that have little or no intercellular space.

The cells in these tissues are widely spaced and have intercellular spaces filled with a dense fluid like structure called intercellular matrix.

They are long cells that have a short hair-like structure called dendrites and a single long thin structure called the axon.

They have different structure depending on the type of muscle cells: they can be long and cylindrical or spindle shaped cells.


They protect the underlying tissues and organs.

Regulate the exchange of materials between the body and external environment.

They protect an organ by forming ligaments and tendons that binds to the muscle or to each other.

They react to a stimulus and generates an impulse, which it then carries to various organs to bring about a response.

Helps different organs of the body to relax and contract and also bring movement to the body.

Task 7

(D1) – Unit 11.1

The Respiratory System.

The breathing in our body occurs due to the respiratory system, which includes the nose, throat, voice box, wind pipe and lungs.



At the top of the respiratory system, the nostrils bring in air into the nose where it is filtered, warmed and moistened. Tiny hairs called Cilia protects the nasal passageways and other parts of the respiratory tract and filter out dust and other particles that enter the nose through the breathed air. In the micro level, the nose has several nerve endings that tell the brain what we are inhaling.

The nose contains a specialized epithelium known as the olfactory epithelium. This is found at the roof of the nasal cavity. The olfactory epithelium contains 3 layers of cells. This is also the place where the cilia is located.

  • Olfactory cells – contains sensitive hairs and nerve fibres.
  • Basal cells – helps make new olfactory cells when the old ones die.
  • Supporting cells – they are formed between the receptor cells to provide support.



Air can also be breathed in through the mouth. The two airway of the nose and mouth meet up at the pharynx. Inside the mouth is the tongue that that several kinds of specialized cells that help it to distinguish taste. It contains taste hair or microvilli which includes the gustatory and transition cells.


It is located at the back of the throat. The pharynx carries both food and air thus, used for both digestion and respiration. The path of the food: the oesophagus lends on to the stomach and the other side is for air called the trachea. The pharynx contains epithelial cells, muscle cells and neurons.


It is a 2cm-3cm tube that extends downwards from the bottom of the larynx (air only pipe) for about 12cm. The walls of the windpipe are made strong by stiff rings of cartilage that keep it open. The trachea is also lined with tiny hairs that sweep foreign particles and fluids out of the airways, keeping them from entering the lungs.


The trachea are made up of smooth muscles and the rings are made up of Hyaline cartilage.


The windpipe divides into two branches and each one of these enteres one of the two lungs of the body. Each branch resembles the limb of a tree dividing into smaller, finer branches called bronchioles. The bronchiles end in tiny air sacs called alveoli. These structures enables fresh air to get to the air sacs which are surrounded by tiny blood vessels or cappilaries. The oxygen passes through these air sacs and travels though the cappilary walls into the bloodstream. At the same time carbon dioxide transfers from the bloodstream into the air sacs.

The bronchioles and the alveolis are made up of specialized epithelial cells and smooth muscles that produce a lubricating mucus that keeps the airways working.

Task 8

(P1) – Unit 6

  1. Red Blood Cell (Eyepiece Graticule)
  • In cm = 0.0015 cm
  • In µm (micrometers) = 0.0015*10000 = 15 µm
  • In inches = 0.0015* 0.393700787 = 0.000590551181 inches
  1. Red Blood Cell (Worksheet)

Magnification ( M )= x7500

Size on worksheet ( I ) = 3.6 cm

Actual Size ( A ) =

= = 0.0048 cm

  • In cm = 0.0048 cm
  • In µm (micrometers) = 0.0048*10000 = 4.8 µm
  • In inches = 0.0048* 0.393700787 = 0.00188976377 inches
  1. Stomata (Worksheet)

Magnification ( M )= x450

Size on worksheet ( I ) = 1.7cm

Actual Size ( A ) =

= = 0.0037 cm

  • In cm = 0.0037 cm
  • In µm (micrometers) = 0.0037*10000 = 37 µm
  • In inches = 0.0037* 0.393700787 = 0.00145669291 inches
  1. Fucus Conceptade Antheridia (Eyepiece Graticule)
  • In cm = 0.07 cm
  • In µm (micrometers) = 0.07*10000 = 700 µm
  • In inches = 0.07* 0.393700787 =0.02755905509 inches

Task 9

(M1) – Unit 6

Results of the measurements of Task 8 in Standard Form.

  1. Red Blood Cell (Eyepiece Graticule)
  • In cm = * cm
  • In µm (micrometers) = 0.0015*10000 = µm
  • In inches = 0.0015* 0.393700787 = 5.90551181*inches
  1. Red Blood Cell (Worksheet)
  • In cm = * cm
  • In µm (micrometers) = 0.0048*10000 = µm
  • In inches = 0.0048* 0.393700787 = 1.88976377*inches
  1. Stomata ( Worksheet)
  • In cm = * cm
  • In µm (micrometers) = 0.0037*10000 = µm
  • In inches = 0.0037* 0.393700787 = 1.45669291*inches
  1. Fucus Conceptade Antheridia (Eyepiece Graticule)
  • In cm = * cm
  • In µm (micrometers) = 0.07*10000 = µm
  • In inches = 0.07* 0.393700787 = 2.755905509*inches

Using the Standard form to determine the difference between two diamters of two cells.

1st Cell : Red Blood Cell ( Worksheet)

2nd Cell : Stomata ( Worksheet)

Difference : Diameter of Red Blood cell ( in cm)– Diameter of Stomata ( in cm)

= * cm - * cm = 1.1* cm

Task 10

(D1) – Unit 6

Ratio of the diamters of the handout provided ( The one of Red Blood Cells and Stomata )

In Centimeters

0.0048 : 0.0037

In Micrometers

4.8 : 3.7

In Inches

0.00188976377 : 0.00145669291

Task 11

(P2) – Unit 6

Height = 4 cm = 4*10mm = 40 mm

Diameter = 0.44 mm

Radius = 0.44/2 = 0.22 mm

Formula for Volume of the artery = πr2h

= 3.14*(0.22)2*40 mm = 60.80 mm3

Task 12

(D2) – Unit 6

Average mass of blood flow in the artery = 6.9*10-3g = 0.0069g

Volume (v) = 60.80 mm3 = 0.0608 mL

Formula : Denisity (p) = mass (m)/volume(v)

Denisity = 0.0069g/0.0608mL = 0.11349 g/mL


eASYtIPS4YOU, 2012. [Online] Available at:

IUPUI, n.d. [Online] Available at: Tissue 07.htm

izzo, d., 2007. [Online] Available at:

RuthON68, 2012. [Online] Available at:

Faizul Islam BTEC L3 Extended Diploma in Applied Science (Year 1)