Physiology Processes of a Developing Human - Assignment Example

Physiology Assignment Q1.A. Answer: The pain pathway in a living being, even if it is a developing human starts in the peripheral sensory neuron. This runs in the spinal cord to synapse in the dorsal horn interneuron that in turn synapses on a ventral horn interneuron. A noxious or painful stimulus will generate a reflex action leading to withdrawal from the source of the painful stimulus. This system develops in a developing human foetus in the gestational age of 7 to 8 weeks with complete development of nociceptive dorsal root ganglion in 19 weeks. This is different from sensation of pain that requires cortical appreciation of the agony and represents a psychological processing of the sense. The pain centre is located at the thalamus, and the thalamic projections start developing from 12 to 16 weeks. The thalamic afferents reach the cortical subplate zone starting from 20 weeks. The thalamic afferent fibres are related to pain perception. Therefore, speaking physiologically, there is enough evidence that a developing human can feel pain sensation. The central effectors of the stress response are corticotrophin-releasing hormone (CRH) and locus coeruleus- norepinephrine (LC/NE)/sympathetic system. The CRH system activates the stress response and is subject to modulation by cytokines, hormones, and neurotransmitters. In response to needle stick or in response to other conditions in the mother's womb, the foetus has been demonstrated generate increased glucocorticoids and as a result, increased heart rate. These evidences suggest that developing human has enough physiologic basis for feeling of pain or stress. Q.1. B. Answer: The presence of D antigen on red cell surface confers Rh-positivity, and absence of D antigen is known as Rh-negativity. The growing embryonic child or the foetus of an Rh-negative mother and an Rh-positive father may be Rh-positive creating a condition where there is difference between the mother's and child's blood. During delivery, a small amount of the child's blood may enter the mother's body, and the mother's body produces antibody against the Rh-positive blood of the fetus. In the next pregnancy, the mother's blood, which already contains antibody against Rh-positive blood, will enter into the foetus' and destroy foetal blood cells. The resulting anemia, which results out of destruction of foetal blood cells, that is, haemolytic anemia may be severe enough to cause foetal death. If the foetus survives to be born, this will invariably lead to severe jaundice in the newborn shortly after birth. Several measures may be adopted to prevent this catastrophe. A regular antenatal care and medical supervision in early pregnancy are needed to detect the risk of the blood type incompatibility. If there is a risk, anti-Rh gamma globulins may be injected to the mother at 28 weeks of gestation and within 72 hours after delivery or miscarriage, abortion, or ectopic pregnancy with a mismatched blood type. The foetal health status can be determined in suspected mismatch and isoimmunization by amniocentesis and cordocentesis. Q2. Answer: This is a mathematical model of a bicycle ride on a mountain terrain. This represents a journey. The vertical axes represent the change in the heart rate in beats per minute of the biker as well as the altitude he covers in metres (represented by the blue line). The horizontal axis represents the timeline in minutes. All these parameters were measured from the start of the journey. At the first stage of the journey at time 0, the altitude is just 20+ metres. The heart rate at that point was approximately 100, and that can be taken as the baseline heart rate. As cycling continues, and the biker reaches the base of the mountain, his heart rate gradually increases until he reaches the middle of the altitude to achieve a maximal heart rate of 180. Before that, the biker reaches another lower peak heart rate of 170. The range of maximal heart rates is, hence, 170 to 180. Although heart rate is a measure of exercise intensity in steady-state activities, and this journey has many variations due to the very nature of altitude biking, yet age subtracted from 220 gives a rough estimate of maximal heart rate. Considering the possibility of errors, the actual maximal heart rate could be 10 beats higher and lower that the estimated value. So the range now changes to 160 to 190 from 170 to 180. As a result, the age range of the biker would be (220-160) to (220-190), that is 60 to 30. This formula again is not applicable to individuals above age 50 due to cardiovascular aging, muscle mass decay, and variations in maximal oxygen consumption (VO2 max). Therefore, the possible age range of the subject would be 30 to 50. The 7- to 8-km journey is the hardest part of the journey to maximal altitude of the mountain. We observe here from the graph that just before the altitude began to rise at 40 m, the heart rate plateaued before that in the range of 160. The moment the altitude began to rise in a steep fashion, to maintain the steady state of rise, the biker had to exert extra effort to continue to rise, and this was reflected in his heart rate changing to 170 per minute, and hence, this is the point at about 12 minutes of journey, the 7- to 8-km journey began. Q3. Answer: From primary evidence from the patients, the disease was caused by an unusual virus, called hantavirus. This was diagnosed to be a new virus or variant of an old virus. This was a virus primarily hosted by mice or rats. The virus was transmitted by rodent's urine, faeces, or saliva and was airborne to be inhaled by human beings. This virus causes increased permeability of alveolar capillary barrier of human lungs that results in pulmonary edema and disturbances in oxygen exchange leading to acute hypoxaemic respiratory failure. This can be viewed as an unregulated overexpression of usual systemic response to an unusual infection. The injury happens to both pulmonary alveolar epithelium and pulmonary capillary endothelium. Increased vascular permeability to proteins leading to disturbed hydrostatic gradient to greatly increase interstitial and alveolar oedema. This disease can be prevented by avoiding contact with mice, field mice, and parckrats and avoiding contact with their droppings and urine. Contacting a physician in the prodromal phase of cough, mild fever, muscles aches, and conjunctivitis is of utmost importance. Q.4. Answer: The disease was indicated to be an acute respiratory illness beginning with influenza-like illness with headache and muscle pain, eventually progressing to respiratory failure due to severe pneumonia. The disease is caused by Hendra virus. This causes disease in horses and then via contact with infected animals is transmitted to human who are in close contact with the infected horses. Fruit bats of the genus Pteropus or common flying fox are the suspected natural hosts of this virus. The infection is widespread and asymptomatic in this animal. Horses, cats, and guinea pigs, all suffer from the disease. Experimental studies have indicated that the animals may incubate the virus for 18 days and although asymptomatic, can be infectious to humans via close contact with infected body fluids through minor cuts and abrasions. Aerosol transmission is not a factor. If the animal has been in the endemic area is considered to be at risk of infection, and the human in contact is at greatest risk of infection within the previous 28 days and in close contact with a horse suspected of being infected. It affects both the human and horses both by an acute, viral flu-like illness, neurological illness suggesting encephalitis, and respiratory involvement in the form of haemorrhagic pneumonitis. To prevent the disease, those in contact with the animals from the endemic areas should wear appropriate personal protective equipment, such as, disposable impermeable gloves, disposable gowns, and face visors that would provide protection to both face and eye. Treatment of these patients is directed to providing intensive supportive care, such as, ventilation and haemodynamic stabilization, and there is some suggestion that early treatment with ribavirin can reduce the illness and severity of the disease. Q. 4. Ans: This picture shows a Western Gray Kangaroo in its nest in Belair National Park in the warm month of October, perhaps taking a nap. The climate is sunny, and it is warm outside. These animals do not have sweat glands, and they are covered with thick fur. These are also warm-blooded; they keep the body temperature at a constant level. This involves ability to cool down as the external temperature rises, and they do it by regulating their metabolic rates. Kangaroos feed mainly in the late afternoon or at night when the temperature drops. During the day, they prefer to rest in the shade as in this picture. The most important responses to heat include use of a nest, den, burrow, or shelter to increase or decrease heat loss or gain. When not active, these use some form of enclosed shelter, which protects them from predators and extremes of temperature. These provide an environment with stable air temperature and high humidity. The most of the tail is kept in shade, and this also preserves body heat. Operation Barbarossa failed due to change in weather due to winter months in Russia. For this, the German army was not at all ready. The troops were not ready with the cold weather gear; the temperature fell down to -22 degrees Centigrade. Exposure to cold increases heat loss and challenges the body's thermal balance. The body responds by shivering, thereby increasing metabolic rate and heat production. Vasoconstriction of skin blood vessels reduces peripheral blood flow. The body does not acclimatize to the cold weather well. To maintain usual intensity, when the core body temperature drops below normal, it needs more exercise, hence more energy, and the storage glycogen gets depleted more easily. Vasoconstriction also reduces blood flow to the muscles, and the anaerobic threshold of the muscles will be reduced, and fatigue will set up sooner. One can be anything to cope up with a situation like this but a soldier in the battlefield winning against the enemy. Physiological adaptation to exposure to cold is a neural process including changes mainly in circulation and endocrine organs. People in arctic and mountainous areas, habituation is the most important physiologic response to extreme cold. The thermoeffector responses like hypothermic, insulative, and metabolic responses are blunted, so shivering and vasoconstrictor responses are blunted. The core body temperature is allowed to decrease more pronouncedly before the body heat production responses are initiated. The thermal conductance in these people is less. This happens due to enhanced vasoconstriction and more considerable decrease in skin temperature. There is lower metabolic heat production and lower rise of blood pressure as a result of habituation. Indeed, the desert living people need far less water that people who are just visitors to the desert. They need less water because they preserve more water by several adaptive mechanisms. There are four primary routes of water loss. Cutaneous and pulmonary evaporation, faeces, and urine. Desert adapted dwellers have developed physiological adaptations that reduce the amount of loss through each of these routes and are able to tolerate significant amount of water loss. The physiological mechanisms to achieve these are adaptive heterothermy, changes in metabolic rate, reduction in renal and digestive water loss, and reduction in pulmonary water loss by cooling exhaled air. Q.5. Ans: Ewa was sucked by a storm system and got unconscious through her journey in the paraglider at an altitude of about 10,000 metres surrounded by lightning with hailstorm, -40 degrees of temperature, and oxygen deprivation. In this altitude, there is less air, and one does not get enough oxygen to breathe. As the individual gets higher and higher, the air gets thinner, and the partial pressure and concentration of oxygen decreases. The drive for breathing is lost due to unconsciousness, and carbon dioxide generated in the body accumulates in the blood to further worsen the situation. The low temperature is the other component. The freezing temperature almost freezes all activities of the body, and the physiological functions come to a standstill. The heart rate slows down, and the stress response is no longer there due to unconsciousness. Breathing becomes shallow, and the frosting reduces the skin temperature but preserves the core heat. The chemical compound of the drug that Annabel died from is MDMA. The use of MDMA depends on the fact that it reduces inhibition and heightens the effect of physical contact. It has stimulant and hallucinogenic properties, reduces anxiety. The hallucinogenic effect results from initial increased release of brain neurotransmitter, serotonin followed by depletion of that. The stimulant effect arises from release of dopamine and results in increased stimulation of the sympathetic nervous system with altered heart rate, blood pressure, mydriasis, increased locomotor activity, and increased body temperature. The range of sensuous and emotional overtones induced by this drug mainly in the form of euphoria happens due to activation of nucleus accumbens, the brains reward centre. These drugs are dangerous due to the fact that they give rise to serotonin syndrome and severe toxic effects, such as, cardiovascular symptoms, hyperthermia, hyponatraemia, memory deficits, and neurotoxic effects. The most dangerous is hyperthermia, not due to the drug per se, but due to excessive activity and overheated and overcrowded environment where these drugs are used. Malignant hyperthermia results in rhabdomyolysis, disseminated intravascular coagulation, and acute renal failure, all potentially life threatening. A developing baby in the mother's womb derives nutrition from the mother. Fish contains omega-3 fatty acids, which are long-chain polyunsaturated fatty acids that are essential for human development, yet not synthesized by humans. This has been found to be an essential component of both neurological and early visual development of the baby. These compounds help develop the brain of the new born due to the fact that brain is 60% Fat, and 20% of that fat is omega-3 fatty acids. These definitely help in development of neurocongnitive function of the baby. Planned cesarean sections increase the health risk of both mother and the baby. There is almost a three-fold increase in maternal morbidity in the form of postpartum cardiac arrest, wound haematoma, hysterectomy, major sepsis, anaesthetic complications, venous thromboembolism, and severe haemorrhage. The adverse neonatal outcomes have been reported to be neonatal respiratory problems, persistent pulmonary hypertension, asphyxia, delayed neurologic adaptation, neonatal intensive care admission, and delayed establishment of breast feeding. [ Despite trying hard I could not accommodate in 7 pages, please have a look, if you desire some parts to be compressed, please let me know, I will make the necessary changes. Since it is question and answer, I did not use in-text citations and bibliography] Read More