The molecules in the image below are able to move across the cell

Which of the following describes characteristics of the earth's crust

Burka [1]

What are the choices?

4 0

3 years ago

In what ways are the new cells (daughter cells), which result from a cell cycle, similar?

slava [35]

Recycling cells division. meoisis theroy

6 0

3 years ago

Describe how blood is pumped and circulated through the body. Include the roles of the various chambers of the heart, the major

Korvikt [17]

The heart is a pump, usually beating about 60 to 100 times per minute. With each heartbeat, the heart sends blood throughout our bodies, carrying oxygen to every cell. After delivering the oxygen, the blood returns to the heart. The heart then sends the blood to the lungs to pick up more oxygen. This cycle repeats over and over again.

The circulatory system is made up of blood vessels that carry blood away from and towards the heart. Arteries carry blood away from the heart and veins carry blood back to the heart.

The circulatory system carries oxygen, nutrients, and hormones to cells, and removes waste products, like carbon dioxide. These roadways travel in one direction only, to keep things going where they should.

The heart has four chambers — two on top and two on bottom:

The two bottom chambers are the right ventricle and the left ventricle. These pump blood out of the heart. A wall called the interventricular septum is between the two ventricles.

The two top chambers are the right atrium and the left atrium. They receive the blood entering the heart. A wall called the interatrial septum is between the atria.

The atria are separated from the ventricles by the atrioventricular valves:

The tricuspid valve separates the right atrium from the right ventricle.

The mitral valve separates the left atrium from the left ventricle.

Two valves also separate the ventricles from the large blood vessels that carry blood leaving the heart:

The pulmonic valve is between the right ventricle and the pulmonary artery, which carries blood to the lungs.

The aortic valve is between the left ventricle and the aorta, which carries blood to the body.

What Are the Parts of the Circulatory System?

Two pathways come from the heart:

The pulmonary circulation is a short loop from the heart to the lungs and back again.

The systemic circulation carries blood from the heart to all the other parts of the body and back again.

In pulmonary circulation:

The pulmonary artery is a big artery that comes from the heart. It splits into two main branches, and brings blood from the heart to the lungs. At the lungs, the blood picks up oxygen and drops off carbon dioxide. The blood then returns to the heart through the pulmonary veins.

In systemic circulation:

Next, blood that returns to the heart has picked up lots of oxygen from the lungs. So it can now go out to the body. The aorta is a big artery that leaves the heart carrying this oxygenated blood. Branches off of the aorta send blood to the muscles of the heart itself, as well as all other parts of the body. Like a tree, the branches gets smaller and smaller as they get farther from the aorta.

At each body part, a network of tiny blood vessels called capillaries connects the very small artery branches to very small veins. The capillaries have very thin walls, and through them, nutrients and oxygen are delivered to the cells. Waste products are brought into the capillaries.

Capillaries then lead into small veins. Small veins lead to larger and larger veins as the blood approaches the heart. Valves in the veins keep blood flowing in the correct direction. Two large veins that lead into the heart are the superior vena cava and inferior vena cava. (The terms superior and inferior don't mean that one vein is better than the other, but that they're located above and below the heart.)

Once the blood is back in the heart, it needs to re-enter the pulmonary circulation and go back to the lungs to drop off the carbon dioxide and pick up more oxygen.

How Does the Heart Beat?

The heart gets messages from the body that tell it when to pump more or less blood depending on a person's needs. For example, when you're sleeping, it pumps just enough to provide for the lower amounts of oxygen needed by your body at rest. But when you're exercising, the heart pumps faster so that your muscles get more oxygen and can work harder.

How the heart beats is controlled by a system of electrical signals in the heart. The sinus (or sinoatrial) node is a small area of tissue in the wall of the right atrium. It sends out an electrical signal to start the contracting (pumping) of the heart muscle. This node is called the pacemaker of the heart because it sets the rate of the heartbeat and causes the rest of the heart to contract in its rhythm.

4 0

3 years ago

Which part of the eye contains receptor cells that are sensitive to light?

Annette [7]

The lining of the back of eye containing two types of photoreceptor cells - rods - sensitive to dim light and black and white - and cones - sensitive to colour. A small area called the fovea in the middle of the retina has many more cones than rods.

6 0

3 years ago

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How does geothermal energy differ from solar energy

neonofarm [45]

Solar Energy:

Of all of the solar technologies, solar thermal systems are by far the most straightforward and the best developed. Architectural Designs are being developed to conserve solar energy by taking advantage of the site and building materials which in turn transform a building into a solar collector. There are many mechanical moving parts within an active solar thermal system.

The makeup of Solar Energy Systems and how solar panels work is best described as follows:

The solar collector (basic unit) is a panel generally made from aluminium, glass, plastic and copper. These panels when fixed to a roof absorb direct sunlight and transfer heat to a fluid that passes through the collector or basic unit. This fluid then flows through pipes into the building where it then heats water or warms the rooms.

Sunlight is converted into electricity by Photovoltaics (solar cells). These solar cells produce an electromotive force in a material as a result of its absorbing ionizing radiation.

In the case of semi-conductors, significant conversion efficiencies have been achieved however in theory this effect is also apparent in solids, liquids and gases. The most commonly used component of the solar semi-conductors is Silicon.

There are a range of different solar power systems currently available. These are

Grid connect solarStand-alone or off-grid solar systemsHybrid solar systemsPortable solar power systemsSolar batteries

More information can be found about these types of systems here.

The usefulness of these Solar Cells in the Space Exploration Program has already been proven in India as well as other countries in the world. The Bhabha Atomic Research Centre in Bombay, have successfully developed Solar Cells which have been tested in the satellite Bhaskara and which also meet part of the power requirement abroad (Gupta, 1981). The likeliness for large-scale power generation to meet energy requirements on earth is even bigger.

Geothermal Energy:

Geothermal Energy is a clean and sustainable power source that comes from heat in the centre of the earth.

Hot molten rock called magma deep inside the earth’s surface has in some places pushed up towards the earth’s crust, resulting in the range of geothermal energy resources to be expanded.

Geysers are produced when water flows over these hot rocks causing steam to rise through crevices in the earth’s crust, which can then be converted into electricity.

There are three types of geothermal energy technologies:

Geothermal Electricity Production: using the earth’s heat to generate electricity.

Geothermal Direct Use: using hot water within the earth to produce heat directly.

Geothermal Heat Pumps: heating and cooling buildings using the shallow ground.

It has only recently become evident that Australia has potential for geothermal energy production, because of the perception that the resources were only found in locations that have active volcanism (which Australia doesn’t have).

However, it has been uncovered that Australia is home to suitable hot sedimentary aquifer and hot rock resources.Two projects are under development in Australia to utilise these resources, and they are hot sedimentary aquifers (HSA), and enhanced geothermal systems (EGS or hot rocks).

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3 years ago

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