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Facial anatomy
Published in Michael Parker, Charlie James, Fundamentals for Cosmetic Practice, 2022
Although most of the fluid in blood is returned to the heart by blood vessels, a small portion remains as extracellular interstitial fluid. This fluid is high in white cells and drains into tiny, blind-ended, highly permeable lymph capillaries which collect fluid from surrounding tissues, carrying it into larger lymph vessels, which, in turn, drain into lymph nodes. Lymphatic vessels entering a lymph node are called afferent lymph vessels, and those leaving lymph nodes are called efferent lymph vessels. The lymphatic system has no central pump like the heart and instead relies on peristalsis of the lymph vessels themselves, as well as contraction of surrounding skeletal muscles. Anything which impairs lymphatic drainage, such as damage to lymph vessels or muscle paralysis, can cause an accumulation of tissue fluid, leading to lymphoedema and swelling. This can give a poor cosmetic result and may also leave patients at risk of infection.
Functional Neurology
Published in James Crossley, Functional Exercise and Rehabilitation, 2021
Neurons clump together to form nerves. Nerves can be either sensory, motor or interconnecting. Sensory nerves, also known as afferent nerves, relay signals from the peripheral tissues and organs to the central nervous system (CNS). Afferent nerves provide the CNS with information regarding our environment. Motor, or efferent nerves, transmit signals from the CNS to the tissues and organs. These signals ‘activate’ or alter the function of peripheral tissues and organs. Motor signals sent from the CNS innervate muscles, making them contract, for example. Interneurons are so called because they communicate between or connect spinal and motor neurons, influencing and modulating neuronal function on yet another level. Nerves congregate in various areas of the body, the entirety of which we call the nervous system.
Basic medicine: physiology
Published in Roy Palmer, Diana Wetherill, Medicine for Lawyers, 2020
A typical nerve cell or neuron has a star-shaped cell body with a fringe of short fibres (dendrites) and one long fibre (axon) which ends in little knobs or terminal buttons. One neuron communicates (synapses) with the next via the dendrites. Nerve cells are readily excited by electrical or other stimuli, and the resulting impulse is conducted along the axon to release a chemical messenger (neurotransmitter) which ‘fires’ the next neuron. The impulse generates an action potential, which is transmitted down the nerve and across the neuromuscular junction, where the axon is expanded to form the motor end plate (Figure 1.2). Nerve fibres are of two main types: sensory (afferent) fibres convey feelings such as pain and touch to the brain, while motor (efferent) fibres stimulate muscles to contract. Sometimes the entire nerve is either motor or sensory? division results in loss of movement or sensation. Other nerves are mixed, e.g. the sciatic nerve, which innervates the skin and muscles of much of the leg. Both nerve conduction and muscle contraction are active processes that require energy expenditure.
A rare complication of laparoscopic Roux-en-Y gastric bypass: case report of gastric remnant necrosis
Published in Acta Chirurgica Belgica, 2023
Astrid Rycx, Hendrik Maes, Yves Van Nieuwenhove
In the first place, small bowel obstruction is a relatively common complication after a LRYGB and can have several causes including hernias, adhesions and stenosis or narrowing at the jejunojejunostomy or the gastrojejunostomy [1,3,5]. Small bowel obstruction due to a stenosis or a kinking at the jejunojejunal anastomosis can result in an important dilatation of the gastric remnant, especially when the biliopancreatic limb is involved. This phenomenon can be compared to the afferent limb syndrome, which is known to be a severe complication after a Billroth II procedure but can in fact occur after every surgery in the stomach region with the construction of an afferent limb. Afferent limb syndrome presents with severe epigastric pain, nausea, vomiting and when left untreated, evolves towards symptoms of shock, peritonitis and necrosis or perforation. Acute dilatation of the gastric remnant due to small bowel obstruction can cause a compromised blood flow and result in necrosis [1–6]. This is certainly a valuable hypothesis for the presented case.
Communication between the gut microbiota and peripheral nervous system in health and chronic disease
Published in Gut Microbes, 2022
Tyler M. Cook, Virginie Mansuy-Aubert
The afferent system provides critical information to the CNS, which integrate the visceral information and produces an effect on peripheral organs via autonomic efferent fibers. Although oversimplified, the sympathetic and parasympathetic efferent neurons are generically segregated based on functions aiding in stress responses (fight or flight) or returning to baseline (rest and digest), respectively. As illustrated Figure 2, sympathetic preganglionic neurons are short and release acetylcholine onto postganglionic neurons triggering the release of mainly norepinephrine onto peripheral organs. Conversely, parasympathetic preganglionic neurons send long projections out to postganglionic neurons which are often located within the target tissue. Both pre- and postganglionic parasympathetic neurons release acetylcholine. Autonomic neurotransmitter release onto peripheral tissues is crucial for regulating key metabolic functions, which are often disrupted in chronic disease.
Treatment with human umbilical cord blood serum in a gentamicin-induced nephrotoxicity model in rats
Published in Drug and Chemical Toxicology, 2022
Naser Mirazi, Fatemeh Baharvand, Reza Moghadasali, Alireza Nourian, Abdolkarim Hosseini
Prior to the implementation of eosin and hematoxylin staining, from the kidney tissues, 5 µ-size sections were deparaffinized and rehydrated. The reagents and stains were bought from Sigma (St. Louis, MO, USA). An Olympus BX-50 microscope, with the integration of a color digital camera (Olympus, Japan, DP-72), was utilized for observing the histological sections. Protective effects of hUCBS on kidney were quantitatively assessed by measuring the glomerular surface area (GA), glomerular volume (GV) and number of proximal tubular cell nuclei (PTN). For each group, 20 superficial cortical glomeruli were selected according to the following criteria: 1) presence of afferent or efferent arterioles at the glomerular vascular pole; 2) presence of the beginning of proximal convoluted tubule at the glomerular urinary pole. GA was measured by outlining a perimeter along the glomerular periphery (Gilbert et al.1991) using image analysis software (Image J v1.53). Assuming glomeruli as spheres, we calculated GV using the following formula: GV = 1.2545 × GA (Rangan and Tesch 2007). PTN was counted in 10 proximal convoluted tubular sections close to the renal corpuscles on which the glomerular measurements were performed. The numbers of epithelial cells were calculated as number of nuclei per 100 µm of perimeter of proximal convoluted tubules using Olympus DP2-BSW application software (v2.2). The images were all taken with a magnification of ×400 from H&E-stained renal tissue sections.