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3 years ago

A barrier made up of several layers that stops pathogens from entering the body is

Biology

1 answer:

wariber [46]3 years ago

8 0

Answer:

A. The Skin

Explanation:

Skin forms a waterproof barrier that prevents pathogens from entering the body.

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DESCRIBE the internal anatomy of skeletal muscle, using each of the following terms: ACTIN, MYOSIN, THIN FILAMENT, THICK FILAMEN

jasenka [17]

INTERNAL ANATOMY OF SKELETAL MUSCLE : SKELETAL MUSCLE IS OTHERWISE CALLED AS STRIATED OR VOLUNTARY MUSCLE. THEIR ACTIVITIES ARE UNDER THE VOLUNTARY CONTROL OF NERVOUS SYSTEM. THEREFORE, THEY ARE KNOWN AS VOLUNTARY MUSCLES. PRIMARY FUNCTION OF THIS MUSCLE IS LOCOMOTION AND CHANGES IN BODY POSTURE.

EACH MUSCLE IS MADE UP OF NUMBER OF MUSCLE BUNDLES OR FASCICLES. THESE FASCICLES ARE HELD TOGETHER BY A COMMON COLLAGENOUS CONNECTIVE TISSUE LAYER CALLED FASCIA.

EACH MUSCLE IS COMPOSED OF NUMEROUS MUSCLE FIBRES AND IT IS MULTINUCLEATED, CROSS STRIATED CYLINDRICAL CELLS. IT IS MADE UP OF SARCOLEMMA OR CELL MEMBRANE ENCLOSING SARCOPLASM (CYTOPLASM) . NUMBER OF EVENLY DISTRIBUTED LONGITUDINAL THREADS CALLED MYOFIBRILS ARE PRESENT IN THE SARCOPLASM.

MUSCLE-FASCICULE-FIBRE-MYOFIBRILS-MYOFILAMENTS

EACH MUSCLE IS AN INDIVIDUAL CELL AND CONSISTS OF FOLLOWING PARTS.

SARCOLEMMA, SARCOPLASM, NUCLEI, MYOFIBRILS, MYOFILAMENTS, MITOCHONDRIA, SARCOPLASMIC RETICULUM.

SARCOLEMMA IS CELL MEMBRANE OF MUSCLE FIBRES AND SARCOPLASM IS SEMIFLUID CYTOPLASM OF MUSCLE.

NUCLEI ARE MULTIPLE IN NUMBER AND OVAL IN SHAPE, PERIPHERAL IN DISTRIBUTION BENEATH THE SARCOLEMMA.

MYOFIBRILS ARE CONTRACTILE UNBRANCHED THREADS SITUATED ALONG THE MUSCLE FIBRE. IT CONSIST OF ALTERNATE A-BAND

AND I-BAND. EACH MYOFIBRILS CONSISTS OF LONGITUDINALLY ARRANGED PROTEIN FILAMENTS SUCH AS THIN FILAMENT CONSISTS OF ACTIN, TROPOMYOSIN, TROPONIN WHEREAS THICK FILAMENT CONSISTS OF MYOSIN . THESE ARE CALLED MYOFILAMENTS.

MITOCHONDRIA PROVIDES ENERGY FOR THE WORK OF MUSCLE FIBRE.

BESIDES THE ABOVE COMPONENTS THERE ARE THREE TYPES OF SUPPORTING TISSUES WHICH HELPS IN ORGANIZATION OF SKELETAL MUSCLES. THESE ARE.

ENDOMYSIUM : IT IS A DELICATE SHEATH OF CONNECTIVE TISSUE WHICH COVERS EACH MUSCLE FIBRE OUTSIDE THE SARCOLEMMA.

PERIMYSIUM : THE MUSCLE FIBRES ARE GROUPED INTO FASCICULI EACH FASCICULUS IS COVERED BY A CONNECTIVE TISSUE SHEATH CALLED PERIMYSIUM.

EPIMYSIUM : THE ENTIRE MUSCLE IS COVERED BY A SHEATH OF CONNECTIVE TISSUE KNOWN AS THE EPIMYSIUM.

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2 years ago

What do all members of a biological species have in common?

notka56 [123]

ACTUALLY, the correct choice is:
A.) They can interbreed and produce fertile offspring.
(For future students seeking help)

(...Not sure why Brainly made that answer verified...)

3 0

3 years ago

Read 2 more answers

What kind of wound occurs when the skin scrapes against a hard surface and tiny blood vessels break in the outer layer of the sk

Elza [17]

A. Abrasion

Reason - cause by scraps on rough surface which breaks skin on outer layer.

8 0

2 years ago

Read 2 more answers

Why does an element have a fixed, uniform composition?

lbvjy [14]

Answer:

Element is a substance that cannot be broken down into simpler substances. Atoms are the smallest particle of an element. An element has a fixed composition because it contains only one type of atom.

7 0

2 years ago

In the 1800s, the Irish wolved the problem of feeding a growing population by planting specifically, they a r e

Otrada [13]

The potato crop devastation occurred in Ireland for not using one single potato species.

Explanation:

Potato became the staple crop of 18th Century Ireland and was easy to grow in the soil of this place. Later, it became the most dependent crop of the people of Ireland which made its supply very demanding leading to the yielding of more than one species of potatoes.

This yielding reduced the variety in the genetics of potatoes that helped in preventing the disease that affect potatoes by making the Irish people susceptible to famine. The Phytopthora bacteria affected the potatoes of North America in the year 1840 and Ireland’s moist weather in that same year made the blight to thrive.

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3 years ago