The circulatory system is responsible for moving blood cells throughout the body.
The gametophyte of a liverwort produces sperm in a structure called <span>antheridium.
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An antheridium<span> or antherida (plural: </span>antheridia<span>) is a </span>haploid<span> structure or organ producing and containing male </span>gametes<span> which is called </span>antherozoids<span> or </span>sperm<span>.</span>
The clinical manifestation which supports this conclusion is that an injury to the brachial plexus which happens during birth. Erb is termed as a paralysis of the arm which is caused by an injury on upper arm's main nerves to be specifically the C5-C6 nerves.
It arrives most commonly on shoulder dystocia when there is a difficult birth. This paralysis can resolve on its own depending on nature of the damage.
1. In the heart, an action potential originates in the (E) sinoatrial node.
The cardiac action potential is a term referring to the change in the membrane potential of heart cells causing the heart to contract. Cardiac action potentials are created by a group of specialized cells capable of generating automatic action potentials and are located in the right atrium of the heart. These cells are called sinoatrial node and sometimes are referred to as the natural pacemaker of the heart. This characterization originates from the fact that sinoatrial node continuously provides action potential and sets the rhythm of the heart function.
2. The sequence of travel by an action potential through the heart is (A) sinoatrial node, atrioventricular node, atrioventricular bundle, bundle branches, Purkinje fibers.
As explained above, the cardiac action potential originates from the sinoatrial node. This action potential then travels through the atrioventricular node, which belongs to the electrical conduction system of the heart and is located between the atria and the ventricles. It is responsible for the electrical connection between the right atrium and the right ventricle. The action potential then travels to the atrioventricular bundle (or bundle of His), another part of the electrical conduction system of the heart. The atrioventricular bundle transmits the electrical impulses from the atrioventricular node to the bundle branches. The bundle branches then send the signal to the Purkinje fibers which send the electrical impulses to the ventricles, causing them to contract.
3. The correct answer is A.
The generation of an action potential in the sinoatrial node causes the contraction of the atria. When the action potential passes from the sinoatrial node to the atrioventricular node, it slows down. This causes the transport of the electrical impulse from the atria to the ventricles to slow down. This delay enables the blood (from the contraction of the atria) to fill the ventricles before their contraction.
4. This statement is true.
The interventricular septum is a structure which divides the two ventricles of the heart and it is composed of two branches, the left bundle and the right bundle branch. When the action potential reaches the interventricular septum, it then travels to the apex of the heart from where it travels upwards along the walls of the ventricles and the ventricular contraction begins.
5. This statement is true.
The bundle branches gradually become Purkinje fibers located in the interior of the ventricular walls. Purkinje fibers are specialized cells and are responsible for conducting cardiac action potentials from the bundle branches to the ventricular walls. This signal transduction causes the muscle of the ventricular walls to contract.
Ecosystem is that it is a community or group of living organisms that live in and interact with each other in a specific environment.
For instance, tropical forests are ecosystems made up of living beings such as trees, plants, animals, insects and micro-organisms that are in constant interaction between themselves and that are affected by other physical (sun, temperature) or chemical (oxygen or nutrients) components.
An ecosystem consists of a community of organisms together with their physical environment.
Ecosystems can be of different sizes and can be marine, aquatic, or terrestrial. Broad categories of terrestrial ecosystems are called biomes.
In ecosystems, both matter and energy are conserved. Energy flows through the system—usually from light to heat—while matter is recycled.
Ecosystems with higher biodiversity tend to be more stable with greater resistance and resilience in the face of disturbances, or disruptive events.
