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Intercostal Nerves
The intercostal nerves are part of the somatic nervous system, and arise from the anterior rami of the thoracic spinal nerves from T1 to T11. The intercostal nerves are distributed chiefly to the thoracic pleura and abdominal peritoneum, and differ from the anterior rami of the other spinal nerves in that each pursues an independent course without plexus formation. The first two nerves supply fibers to the upper limb and thorax; the next four distribute to the walls of the thorax; the lower five supply the walls of the thorax and abdomen. The 7th intercostal nerve ends at the xyphoid process of the Human sternum, sternum. The 10th intercostal nerve terminates at the navel. The 12th (subcostal nerve, subcostal) thoracic is distributed to the walls of the abdomen and groin. Each of these fibers contains around 1300 axons. Unlike the nerves from the autonomic nervous system that innervate the visceral pleura of the thoracic cavity, the intercostal nerves arise from the somatic nerv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intercostal Muscle
The intercostal muscles comprise many different groups of muscle Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contra ...s that run between the ribs, and help form and move the chest wall. The intercostal muscles are mainly involved in the mechanical aspect of breathing by helping expand and shrink the size of the chest cavity. Structure There are three principal layers: # External intercostal muscles also known as intercostalis externus aid in quiet and forced inhalation. They originate on ribs 1–11 and have their insertion on ribs 2–12. The external intercostals are responsible for the elevation of the ribs and bending them more open, thus expanding the transverse dimensions of the thoracic cavity. The muscle fibers are directed downwards, forwards and medially in the anteri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parietal Pleura
The pleurae (: pleura) are the two flattened closed sacs filled with pleural fluid, each ensheathing each lung and lining their surrounding tissues, locally appearing as two opposing layers of serous membrane separating the lungs from the mediastinum, the inside surfaces of the surrounding chest walls and the diaphragm. Although wrapped onto itself resulting in an apparent double layer, each lung is surrounded by a single, continuous pleural membrane. The portion of the pleura that covers the surface of each lung is often called the visceral pleura. This can lead to some confusion, as the lung is not the only visceral organ covered by the pleura. The pleura typically dips between the lobes of the lung as ''fissures'', and is formed by the invagination of lung buds into each thoracic sac during embryonic development. The portion of the pleura seen as the outer layer covers the chest wall, the diaphragm and the mediastinum and is often also misleadingly called the parietal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lactation
Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process naturally occurs with all sexually mature female mammals, although it may predate mammals. The process of feeding milk in all female creatures is called ''nursing'', and in humans it is also called ''breastfeeding''. Newborn infants often produce some milk from their own breast tissue, known colloquially as witch's milk. In most species, lactation is a sign that the female has been pregnant at some point in her life, although in humans and goats, it can happen without pregnancy. Nearly every species of mammal has teats; except for monotremes, egg-laying mammals, which instead release milk through ducts in the abdomen. In only a handful of species of mammals, certain bat species, is milk production a normal Male lactation, male function. ''Galactopoiesis'' is the maintenance of milk production. This stage requires prolactin. Oxytocin is cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myoepithelial Cell
Myoepithelial cells (sometimes referred to as myoepithelium) are cells usually found in glandular epithelium as a thin layer above the basement membrane but generally beneath the lumen (anatomy), luminal cells. These may be positive for ACTA2, alpha smooth muscle actin and can contract and expel the secretions of exocrine glands. They are found in the sweat glands, mammary glands, lacrimal glands, and salivary glands. Myoepithelial cells in these cases constitute the basal cell layer of an epithelium that harbors the epithelial Progenitor cell, progenitor. In the case of wound healing, myoepithelial cells reactively cell growth, proliferate. Presence of myoepithelial cells in a hyperplasia, hyperplastic tissue proves the benignity of the gland and, when absent, indicates cancer. Only rare cancers like adenoid cystic carcinomas contains myoepithelial cells as one of the malignant components. It can be found in endoderm or ectoderm. Markers Myoepithelial cells are true epithelial cel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxytocin
Oxytocin is a peptide hormone and neuropeptide normally produced in the hypothalamus and released by the posterior pituitary. Present in animals since early stages of evolution, in humans it plays roles in behavior that include Human bonding, social bonding, love, reproduction, childbirth, and the Postpartum period, period after childbirth. Oxytocin is released into the bloodstream as a hormone in response to Human sexual activity, sexual activity and during childbirth. It is also available in Oxytocin (medication), pharmaceutical form. In either form, oxytocin stimulates uterine contractions to speed up the process of childbirth. In its natural form, it also plays a role in maternal bonding and lactation, milk production. Production and secretion of oxytocin is controlled by a positive feedback mechanism, where its initial release stimulates production and release of further oxytocin. For example, when oxytocin is released during a contraction of the uterus at the start of c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanoreceptor
A mechanoreceptor, also called mechanoceptor, is a sensory receptor that responds to mechanical pressure or distortion. Mechanoreceptors are located on sensory neurons that convert mechanical pressure into action potential, electrical signals that, in animals, are sent to the central nervous system. Vertebrate mechanoreceptors Cutaneous mechanoreceptors Cutaneous mechanoreceptors respond to mechanical stimuli that result from physical interaction, including pressure and vibration. They are located in the skin, like other cutaneous receptors. They are all innervated by Aβ fibers, except the mechanorecepting free nerve endings, which are innervated by A delta fiber, Aδ fibers. Cutaneous mechanoreceptors can be categorized by what kind of sensation they perceive, by the rate of adaptation, and by morphology. Furthermore, each has a different receptive field. By sensation * The Slowly Adapting type 1 (SA1) mechanoreceptor, with the Merkel corpuscle end-organ (also known as M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cervical Plexus
The cervical plexus is a nerve plexus of the anterior rami of the first (i.e. upper-most) four cervical spinal nerves C1-C4. The cervical plexus provides motor innervation to some muscles of the neck, and the diaphragm; it provides sensory innervation to parts of the head, neck, and chest. Anatomy They are located laterally to the transverse processes between prevertebral muscles from the medial side and vertebral (m. scalenus, m. levator scapulae, m. splenius cervicis) from lateral side. There is anastomosis with accessory nerve, hypoglossal nerve and sympathetic trunk. It is located in the neck, deep to the sternocleidomastoid muscle. The branches of the cervical plexus emerge from the posterior triangle at the nerve point, a point which lies midway on the posterior border of the sternocleidomastoid. Relations The cervical plexus is situated deep to the sternocleidomastoid muscle, internal jugular vein, and deep cervical fascia. It is situated anterior to the mid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supraclavicular Nerve
The supraclavicular nerve is a cutaneous (sensory) nerve of the cervical plexus that arises from the third and fourth cervical (spinal) nerves. It emerges from beneath the posterior border of the sternocleidomastoid muscle, then split into multiple branches. Together, these innervate the skin over the shoulder. The supraclavicular nerve can be blocked during shoulder surgery. Anatomy Origin The supraclavicular nerve is a branch of the cervical plexus that arises from cervical (spinal) nerves C3-C4 with the predominant contribution from C4. Course It emerges at the posterior border of the sternocleidomastoid muscle alongside the other three cutaneous branches of the cervical plexus, then promptly divides into several branches. The nerves descend in the posterior triangle of the neck beneath the platysma muscle and the deep cervical fascia. Near the clavicle, the supraclavicular nerves perforate the fascia and the platysma muscle to become cutaneous. They are arranged, acc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intercostales Interni
The internal intercostal muscles (intercostales interni) are a group of skeletal muscles located between the ribs. They are eleven in number on either side. They commence anteriorly at the sternum, in the intercostal spaces between the cartilages of the true ribs, and at the anterior extremities of the cartilages of the false ribs, and extend backward as far as the angles of the ribs, hence they are continued to the vertebral column by thin aponeuroses, the posterior intercostal membranes. They pull the sternum and ribs upward and inward. Structure Their fibers are also directed obliquely, but pass in a direction opposite to those of the external intercostal muscles. The internal intercostal muscles originate from the costal groove of the rib and insert into the superior aspect of the rib below in a direction perpendicular to the external intercostal muscles. It is this arrangement that allows these muscles to facilitate exhalation. For the most part, they are muscles of exh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transversus Thoracis Muscle
The transversus thoracis muscle (), also known as triangularis sterni, lies internal to the thoracic cage, anteriorly. It is usually a thin plane of muscular and tendinous fibers, however on athletic individuals it can be a thick 'slab of meat', situated upon the inner surface of the front wall of the chest. It is in the same layer as the subcostal muscles and the innermost intercostal muscles. Structure It arises on either side from the lower third of the posterior surface of the body of the sternum, from the posterior surface of the xiphoid process, and from the sternal ends of the costal cartilages of the lower three or four true ribs. Its fibers diverge upward and lateralward, to be inserted by slips into the lower borders and inner surfaces of the costal cartilages of the second, third, fourth, fifth, and sixth ribs. The lowest fibers of this muscle are horizontal in their direction, and are continuous with those of the transversus abdominis; the intermediate fibers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internal Mammary Artery
The internal thoracic artery (ITA), also known as the internal mammary artery, is an artery that supplies the anterior chest wall and the breasts. It is a paired artery, with one running along each side of the sternum, to continue after its bifurcation as the superior epigastric and musculophrenic arteries. Structure The internal thoracic artery arises from the anterior surface of the subclavian artery near its origin. It has a width of between 1-2 mm. It travels downward on the inside of the rib cage, approximately 1 cm from the sides of the sternum, and thus medial to the nipple. It is accompanied by the internal thoracic vein. It runs deep to the abdominal external oblique muscle, but superficial to the vagus nerve. In adults, the internal thoracic artery lies closest to the sternum at the first intercostal space. The gap between the artery and lateral border of the sternum increases when going downwards, up to 1.1 cm to 1.3 cm at the sixth intercostal s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
