Physiology, Sensory Receptors

The human body can achieve an understanding of the world through its sensory systems. Sensory systems are widespread throughout the body including those that detect the world directly from the outside (exteroreceptors), those that detect information from internal organs and processes (interoceptors), and those detecting sense of position and load (proprioception).[1][2][3][1] Sensory receptors occur in specialized organs such as the eyes, ears, nose, and mouth, as well as internal organs. Each receptor type conveys a distinct sensory modality to integrate into a single perceptual frame eventually. This information is achieved by the conversion of energy into an electrical signal by specialized mechanisms. In this report, we will discuss a basic overview of sensory systems, focusing on sensory receptors

Physiology, Defecation

Defecation is the term given for the act of expelling feces from the digestive tract via the anus. It is a complex function that requires coordinated involvement from the gastrointestinal system, the nervous system, as well as the musculoskeletal system.[1]  The frequency of defecation within a 24-hour period varies depending on age and diet, but most people tend to have a bowel movement 1 to 3 times daily.[2

Physiology, Breast Milk

The production of breast milk initiates in larger amounts between 2 and 4 days after the birth of the baby and the breastmilk is said to have 'come in'. It is the sole best source of nutrition for an infant, providing an adequate amount of nutrients, growth factors, and antibodies required for the nourishment of the baby. Breast milk should be exclusively used for nutrition until 6 months of age after which breastmilk should be used in addition to complementary foods for at least 12 months of age. [1

Synergistic effect of energy drinks and overweight/obesity on cardiac autonomic testing using the Valsalva maneuver in university students

BACKGROUND: Obesity and caffeine consumption may lead to autonomic disturbances that can result in a wide range of cardiovascular disorders. OBJECTIVES: To determine autonomic disturbances produced by the synergistic effects of overweight or obesity (OW/OB) and energy drinks. DESIGN: Cross-sectional, analytical. SETTING: Physiology department at a university in Saudi Arabia. SUBJECTS AND METHODS: University students, 18–22 years of age, of normal weight (NW) and OW/OB were recruited by convenience sampling. Autonomic testing by the Valsalva ratio (VR) along with systolic and diastolic blood pressure, pulse pressure, and mean arterial blood pressure were measured at baseline (0 minute) and 60 minutes after energy drink consumption. MAIN OUTCOME MEASURE(S): Autonomic disturbance, hemodynamic changes. RESULTS: In 50 (27 males and 23 females) subjects, 21 NW and 29 OW/OB, a significant decrease in VR was observed in OW/OB subjects and in NW and OW/OB females at 60 minutes after energy drink consumption. Values of systolic and diastolic blood pressure, pulse pressure and mean arterial blood pressure were also significantly higher in OW/OB and in females as compared to NW and males. BMI was negatively correlated with VR and diastolic blood pressure at 60 minutes. CONCLUSION: Obesity and energy drinks alter autonomic functions. In some individuals, OW/OB may augment these effects. LIMITATIONS: Due to time and resource restraints, only the acute effects of energy drinks were examined

Effect of energy drink consumption on baroreceptor sensitivity in young normal weight and overweight/obese males

Objectives: There is lack of evidence exploring sympathetic effect by baroreceptor sensitivity in obese consuming energy drink. The purpose of this study was to investigate the acute effect of energy drink on individuals baroreceptor sensitivity in young healthy normal weight and overweight/obese males. Methods: This cross-sectional study was performed in the Department of Physiology, Imam Abdulrahman Bin Faisal University, Kingdom of Saudi Arabia. After getting ethical approval, 25 male participants were recruited by convenient sampling and informed consent was obtained. Participants were grouped into normal weight and overweight/obese on basis of body mass index. Finger arterial blood pressure was recorded with Finometer® at baseline, 30min and 60 minutes in the post-energy drink period and baroreceptor sensitivity was calculated. As data was not normally distributed it was log transformed. Results: The baseline baroreceptor sensitivity was lower (P<0.05) in overweight/obese compared to normal weight participants. Baroreceptor sensitivity reduced significantly (P<0.05) at 60 minutes after energy drink consumption in the whole cohort of both normal weight and overweight/obese. Baroreceptor sensitivity remained lower in overweight/obese compared to normal weight at 60min but the difference was not significant. Conclusion: Consumption of energy drink acutely reduced baroreceptor sensitivity in both normal weight and obese young healthy males with an earlier onset of effect in overweight/obese indicating enhanced sympathetic activity. Energy drinks consumption could place the obese in a more vulnerable state to hypertension and arrhythmia