Human Physiology Lecture Notes

Difference between Primary and Secondary Myofilaments – Comparison Table


primary vs secondary myofilaments

Primary Myofilaments vs Secondary Myofilaments
(Difference between the Primary Myofilaments and Secondary Myofilaments of Myofibrils)

Myofilaments are the filaments of myofibrils (myofibrils are the basic structural unit of muscle cells). The myofilaments are composed of proteins particularly actin and myosin. The detailed structural analysis shows that the muscle sarcomere composed of bundles of two types of myofilaments called primary myofilaments and secondary myofilaments. The present post discusses the difference between the Primary Myofilaments and Secondary Myofilaments with a comparison table.

Learn more: Difference between A-Band and I-Band

Difference between Primary and Secondary Myofilaments

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Difference between Tropic Movements and Nastic Movements – Comparison Table


Tropic vs Nastic Movments

Tropic Movements vs Nastic Movements
Similarities and Differences between Tropic Movements and Nastic Movements in Plants

Tropic movements and Nastic movements are the two types of induced or paratonic movements of curvature in plants.

Tropic movements: The paratonic (induced) movement of growth is called tropic movements. Here the stimuli are external and unidirectional. Example: phototropic movements (movement towards the light) geotropic movements (movement towards gravity), chemotropic movements (movement towards chemicals) etc.

What is Phototropism

Nastic movements: The paratonic movements of variations are called nastic movements. Here the stimuli are external and diffused (not unidirectional). Example: nyctinastic movements (movements in response to darkness), Seismonastic movements or Thigmonastic movements (movements in response to touch) etc.

What is Nastic Movment

The present post discusses the Similarities and Differences between Tropic Movements and Nastic Movements in Plants with a Comparison Table.

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Zoology lecture notes and study materials

Difference between Keratinized and Non-keratinized Epithelial Tissues


Keratinized vs Nonkeratinized Epithelium

Keratinized vs Non-keratinized Epithelium
Difference between Keratinized and Non-keratinized Epithelial Tissues

Epithelium constitutes the outer layer of body surfaces, linings of the alimentary canal and the walls of hollow structures. It covers the internal or external surfaces of the body.

The functions epithelial tissue is to protect the underlying tissues from physical damages, infection, desiccation, UV radiation and heat loss. Based on the presence of Keratin, the epithelial tissues are categorized into Keratinized epithelium and Non-keratinized epithelial tissues.

Keratins are a diverse group of structural proteins that form the intermediate filament network and they provide the structural integrity of keratinized epithelial cells.

The present post discusses the Difference between Keratinized and Non-keratinized Epithelial Cells.

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Difference between B-Cells and T-Cells – Comparison Table


B Lymphocytes vs T Lymphocytes

B-Cells vs T-Cells
(Similarities and Differences between B-Lymphocytes and T-Lymphocytes)

Lymphocytes are the key cells of the immune system and they are responsible for the adaptive immune response of an organism. They are also responsible many of the immunological characteristics such as specificity, diversity, memory and self/non-self recognition. Lymphocytes constitute about 20 – 40% of the body’s White blood cells and 99% of the cells of the lymph. Lymphocytes are broadly classified into THREE populations based on their function, lifespan, cell surface components and most importantly their place of maturation. They are B-Lymphocytes (B-Cells), T-Lymphocytes (T-Cells) and Natural Killer Cells (NK Cells).

B-Lymphocytes (B-Cells):

They mature in the bone marrow or bursa (in birds). B-cells possess membrane bound immunoglobulins which acts as the receptors for the antigens. They are involved in the humoral (antibody mediated) immune responses.

Learn more: Cell Mediated vs Humoral Immunity

T-Lymphocytes (T-Cells):

They mature in the thymus, hence the name. T-cells possess receptors for antigens on their surface but it is structurally different from immunoglobulins. They are involved in Cell-mediated immune responses.

The present post discusses the Similarities and Differences between B-Lymphocytes (B-Cells) and T-Lymphocytes (T-Cells) with a Comparison Table.

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Human Physiology Lecture Notes

Difference between A-Band and I-Band of Sarcomere – Comparison Tab


A-band vs I-band

A-Band vs I-Band
Difference between A-Band and I-Band of a Sarcomere

The basic structural and functional unit of a striated muscle is called the Sarcomere. The sarcomere is the repeating units of a striated muscle occur between two Z-lines. This gives the striated appearance of the skeletal or cardiac muscles. The sarcomere composed of myofibrils, an array elongated contractile protein threads found in striated muscle cells.

There are two types of myofibrils in the sarcomere called thin filaments and thick filaments. The thin filaments are made of protein called Actin and the thick filaments are made of proteins called Myosin. The actin and myosin filaments in a sarcomere are arranged in a specific manner so that their overlapping and interlocking patterns produce distinct bands when they are observed under a microscope. These bands are technically called as A-bands (Anisotropic) and I-Bands (Isotropic).

The present post discusses the Difference between A-bands and I-bands with a comparison table.

Sarcomere diagram

Structure of Sarcomere (Source: Wikipedia)

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