Answer:
Absorption and secretion would be impossible within the digestive tract.
Explanation:
Epithelium is one of the tissues found in humans. It is classified as either simple or stratified depending on the number of cell layers. Simple epithelial tissues have one layer of cells while stratified have many layers of cells. Based on the shape, epithelial tissues can either be squamous, columnar or cuboidal.
Due to the single-layer of the simple epithelial tissues, they line the walls of secretory or absorptive organs e.g organs of digestive tract. The stratified epithelium is majorly for protective function due to the number of cell layers it possess and not a good type of epithelium for locations where absorption and secretion of substances is common e.g digestive tract.
Hence, if a genetic mutation causes a person's digestive tract to have stratified columnar epithelium instead of simple columnar epithelium, ABSORPTION AND SECRETION of chemical substances, which is a key feature of organs (stomach, intestine) that make up digestive tracts, will be impossible.
Answer:
The prolonged electrical depolarization of cardiac muscle cells -that occurs during contraction- is due primarily to the persistent influx of calcium ion
Explanation:
The action potential of the heart muscle is longer with respect to skeletal muscle (around 300 milliseconds), and this is due to the activity of calcium (Ca⁺⁺ ) in the intracellular compartment.
The initial depolarization of cardiac muscle fiber depends on the entry of sodium (Na⁺) into the cell. However, for the action potential to occur and be maintained, Ca⁺⁺ must increase its cytoplasmic levels, which depends on:
- The increase in intracellular sodium induces the release of Ca⁺⁺ from the sarcoplasmic reticulum.
- Calcium entry from the extracellular space through the voltage dependent Ca⁺⁺ channels.
- The entry of extracellular Ca⁺⁺ causes the release of more Ca⁺⁺ ions by the sarcoplasmic reticulum, further increasing its intracellular concentration.
This is how the ion that guarantees the duration of the action potential of the cardiac muscle cell is the Ca⁺⁺.
Learn more:
Calcium, sodium and cardiac muscle cells brainly.com/question/4473795
It is true that r-related species have a short life span and an early reproduction cycle. R-related species also known as r-strategist have a short and simple life span. Due to their simple life span, their nutrient exchange rate with the environment is rapid. Unlike K-selected species, they have the ability to reproduce at a young age. They reproduce a large number of off-springs, but many of their off-springs tend to die before attainment of their reproductive age.
Surface area is an important factor in limiting cell growth because
a. the cell can burst if the membrane becomes too large.
b. materials cannot enter the cell if the surface is too large.
c. the cell may become too large to take in enough food and to remove enough wastes.
d. waste products cannot leave the cell if the cell is too small.
Answer:
c. the cell may become too large to take in enough food and to remove enough wastes.
Explanation:
The exchange of substances with surroundings is done by cells by the process of diffusion. The rate of diffusion of substances requires the presence of a higher surface area than volume. As the cells become larger, their surface area is reduced with respect to the volume. Therefore, larger cells can not support the diffusion of substances in and out as required for its proper functioning. If cells are allowed to grow continuously, they will not be able to intake the requires materials such as food and to release the waste outside.
Answer:
Air is matter because it's make up of a mix of different gases. These are made up of elements such as hydrogen, oxygen, and nitrogen, which are made of matter.
Explanation:
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