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.
The monomer units of the carbohydrates vary in their total numbers extensively. Moreover, positions of the carbonyl groups along with the orientation of the hydroxyl groups also vary in the carbohydrates' monomers. The presence of any modification is also variable.
On the other hand, the nucleic acids have only 4 monomeric units. The linkages between the nucleic acid residues have less geometry than the glycosidic linkages.
Carbohydrates attached to lipids and to proteins extend from the outward facing surface to the membrane. The second factor that leads to fluidity is the nature of the phospholipids themselves
Answer:
Kinase-connected receptors or receptor tyro-sine kinases react for the most part to protein and chemical go between. A solitary trans membrane helix interfaces the extracellular restricting area to the intra-cellular space. e.g. insulin, development factors. The official of the ligand triggers the commencement of a few succession of occasions related with phosphorylation of proteins, this is called protein kinase course.
For instance, the official of development hormone to the receptor in the plasma layer causes dimerization (by the actuation of Janus kinase 2, JAK2) of the receptor (conformation change) that bring about auto-phosphorylation of tyro-sine buildups. The official of SH2-space (src homology) protein (Grb-2) to the phosphorylated tyro-sine buildups invigorates cell development through a course of protein phosphorylation.
a). RTKs are the trans-membrane receptors, which have a ligand restricting site on the extracellular area and tyro-sine authoritative on the intra-cellular space. In the event that it comes up short on the extracellular area, the ligand can't tie to the receptor site, so no cell reaction happens.
b). On the off chance that it does not have the intra-cellular space, the ligand can tie to the receptor site, the receptor can't impart signs tot eh intra-cellular area because of the absence of intra-cellular space.
