Acetylcholine then binds to receptors on the muscle fibre membrane (sarcolemma) causing depolarisation. A wave of depolarisation travels down tubules (T system). T system depolarisation leads to Ca2+ release from stores in sarcoplasmic reticulum. Ca2+ binds to proteins in the muscle, which leads to contraction. Acetylcholinesterase in the gap rapidly breaks down acetylcholine so that contraction only occurs when impulses arrive continuously.
The brain sends an impulse to the muscle, which then travels down through the motor neuron to the neuromuscular junction, to which it then lets out acetylcholine. The impulse then travels through the sarcolemma and transverse tubules (T- tubules). While the impulse passes through the transverse tubules, the sarcoplasmic reticulum releases calcium
When an AP reaches the presynaptic neuron, the voltage-gated calcium channels open and C++ flows into the cell. C++ binds to the vesicles containing the neurotransmitter and causes these to move toward the presynaptic membrane where the vesicles release the neurotransmitter into the synaptic cleft (exocytosis). The neurotransmitter
The brain and nervous system are able to control both the heart rate and blood pressure due to the two carotid sinuses, that are located in the right and left carotids, and the aortic arch. The nerve endings on the outer layer of both the carotid sinuses and the aortic arch form two different nerves, which are known as baroreceptors. Baroreceptors, or receptors for pressure, send information concerning what is happening in blood vessels, particularly about stretch. The more pressure in blood vessels, the more they stretch. These pressure receivers send multiple signals to the Medulla oblongata and brainstem.
When the both sympathetic and parasympathetic ganglion direct to the same organ or gland the total function of the gland is carried by the input signals given by chain ganglia and the terminal ganglia. E.g. the sympathetic ganglion can increase the heart rate and the parasympathetic ganglion can decrease the heart rate. Terminal ganglia in the sympathetic nervous system receive impulses from the head, neck, thoracic and lumber regions. Terminal ganglia of the parasympathetic system receive impulses from the lower abdominal region as well as the pelvic cavity.
Increased breathing rate Exercise results in an increase in the rate and depth of breathing. During exercise your muscles demand more oxygen and the corresponding increase increase in carbon dioxide production stimulates faster and deeper breathing. The capillary network surrounding the alveoli expands, increasing blood flow to the lungs and pulmonary diffusion. A minor rise in breathing rate prior to exercise is known as an anticipatory rise. When exercise begins there is an immediate and significant increase in breathing rate, believed to be a result of receptors working in both the muscles and joints.
After their job is accomplished, the osteoclast undergo apoptosis. This process proceed to the reversal stage, during which coupling signals are sent to attract osteoblast into resorptive sites. Resorption is then turned off and the formation stage follows. The osteoclasts synthesize bone matrix and facilitate its mineralization. Calcium and phosphate ion are deposited into the matrix, leading to hardening of the bone.
• Microglia: act as the first and main form of active immune defense in the central nervous system (CNS). • Ependymal cell: filters blood to make cerebrospinal fluid (CSF), the fluid that circulates through the CNS. PNS glia • Satellite cell: role as a regulator of neuronal microenvironment is further characterized by its electrical properties which are very similar to those of
For example a bicep curl, the bicep is the agonist causing the movement and the triceps are the antagonist going in the opposition to the bicep muscles. The fixator muscle is the muscle that supports the origin of the agonist and the joint that the origin moves over so it can help the agonist muscle work efficiently. There are different types of muscle contractions. These are; isotonic, isokinetic and isometric, under isotonic there are two types, concentric and eccentric. Isotonic contractions are ones where the muscle is caused to change length when it contracts and there is movement of a part of the body.
The Renin-Angiotensin System Renin is synthesized and stored in an inactive form called prorenin in the juxtaglomerular cells of the kidneys. These cells are modified smooth muscle cells located in the walls of the afferent arterioles. When the arterial pressure falls, intrinsic reactions in the kidneys themselves cause many of the prorenin molecules in the JG cells to split and release renin. Most of the renin enters the renal blood and then passes out of the kidneys to circulate throughout the entire body .
Angiotensin II acts as a mediator for the Renin-Angiotensin-Aldosterone system, it does this by activating Angiotensin type 1 (AT1) receptor and Angiotensin type 2 (AT2) receptor. The AT1 receptors stimulate the production of aldosterone from the adrenal zona glomerulus. The receptors are found in vasculature,
MAPK can now activate a transcription factor, such as MYC. In more details, receptor-linked tyrosine kinase as the epidermal growth factor (EGFR) is activated by extracellular ligand, epidermal growth factor (EGF). This activates the tyrosine kinase activity of the cytoplasmic domain of the receptor. The EGFR becomes phosphorylated on tyrosine residues. Next, GRB2 binds to the phosphotyrosine residues of the activated receptor.
The brain is the control centre for the nervous system The nervous system is split into two; -central nervous system; *brain *spinal cord -peripheral nervous system; *sensory division- informs the central nervous system of outer changes *somatic division- sends instructions of movement to different muscles *autonomic division- controls the running of inner organs -autonomic nervous system -somatic nervous system
Receptors Receptors specifically bind to target molecules and initiate a response in the target cell. In most cases, these receptors are transmembrane proteins on the cell surface. When an extracellular signal molecule binds to them, they release a cascade of intracellular signals that alter the behavior of the cell1. In this experiment, we will be adding compounds, such as eserine and acetylcholine to a muscle cell bath and measuring its effect, in this case being force of contraction. These compounds target muscarinic acetylcholine receptors to produce their response, which will be made into a concentration/effect curve.