The body receives oxygen from the lungs and transmits it to your muscles through your bloodstream. The heart controls the flow of blood throughout the body and your heart rate is a factor of that flow. Therefore when your muscles work harder and require more oxygen, your heart rate increases to meet the needs to maintain a consistent internal state, the harder you work the faster your heart pumps. The probable homeostatic responses to changes in the internal environment during exercise to the breathing rate, exercise will increase the demands on your body to supply the fuel it needs to perform. Your body’s need for oxygen will increase.
This is the body’s response to a threat or danger. During this reaction, stress hormones epinephrine and norepinephrine are released from the adrenal glands. Then the sympathetic nervous system increases heart rate and respiration, slows digestion, and sends blood flow to major muscle groups giving the body energy and strength. This was what happened to
The endocrine system carries chemical messengers to adjust bodily functions. During forms of exercise, the body’s internal environment is altered and placed under a considerable amount of stress. Through homeostatic feedback mechanisms, the body is able to maintain a healthy internal environment and quickly return to normal after exercise ends. These homeostatic mechanisms respond to
This will cause an action potential to spread down to the T- tubules and “electrical chemical signals = shocks” the sarcoplasmic reticulum into releasing calcium ions. Then the calcium is released from the sarcoplasmic reticulum to the sarcoplasm. 5. Calcium is restored/ reused in the sarcoplasmic reticulum. Just as concentration results from the release of calcium ions stored in the sarcoplasmic reticulum, contraction ends and relaxation begins as Calcium is
Case Study Questions: 1.) Explain the renin-angiotensin-aldosterone system. When the kidneys sense decreased profusion pressure, they try to increase this pressure by increasing blood volume through the renin-angiotension-aldosterone system. Once the decreased pressure is sensed renin is released, which increases conversion of angiotension to angiotension I. Angiotension I is in turn converted to angiotension II by the angiontension converting enzyme (ACE). Angiotension II causes vasoconstriction, which raises the blood pressure.
Homeostasis is the process of maintaining a constant internal environment in response to changes in the external environment. Homeostatic mechanisms are for regulating; body temperature, blood glucose, heart rate and breathing rate. Regulating the internal environment of a human is achieved by negative feedback; this is a constant process. Conditions within the body changes and receptors detect that change; receptors are found in the skin, around vital organs and the hypothalamus. This information of change that is detected by the receptors are then passed to the control centre in the hypothalamus which monitors the changes, when the change in environment fall too far outside the normal range of values the negative feedback response begins.
‘Stress’ refers to the psychological and physiological responses which occur when we perceive a threat and don’t have the resources to cope with it. These threats are known as ‘stressors’. There are three stages: the alarm reaction stage, the resistance stage and the exhaustion stage. The alarm reaction stage is where the autonomic nervous system is activated, triggering the ‘fight or flight’ response. Dilated pupils, saliva inhibition and faster heartbeat are examples of what happens to the body during this stage to enable us to prepare for action, whether it be to fight or to run away from the threat.
SAM If a stressor is percieved as acute by the hypothalamus, its physiological response occurs through the sympathomedullary pathway, made up of the sympathetic adrenal medullary system (SAM) and the sympathetic branch (sympathetic nervous system or SNS). The sympathetic branch (SNS) of the autonomic nervous system (ANS/ self regulating) is activated, the SNS triggers the evolutionary fight or flight response enabling the body to prepare itself in order to deal with the stressor at hand (the flight or flight response is an adaptive response because it maximises our chances of survival under threat). From there the SNS stimulates the production of adrenaline and noradrenaline, needed to “fight” or “flee”, through the adrenal medulla. Some of the physiological results of this production of adrenaline and noradrenaline are pupil dilation allowing the individual to view the threat more clearly (as increased pupil size allows for more light to be let in enabling better vision) and an accelerated heart rate whereby blood can be more rapidly directed to the parts of the body likely to need it like the skeletal muscles as the acceleration allows for a greater blood flow. Other activities are supressed by the fight/flight response so that we maximise diversion of resources to the parts of our body that need it, so for instance bowel movement will decrease and salivation will slow down as it’s not essential that we digest our food (in that moment).
‘Discuss the extent to which research suggests that stress may affect the immune system’ 12 marks Stress is defined in three ways – one is a response to or reaction to something in the environment. The second is as a stimulus or a stressor, for example a feature of the environment that produces a stress response. Finally, is a lack of fit between the perceived demands of the environment and the perceived ability to cope with those demands, this is shown by the transactional model. When stress occurs in the body, the long term effects are shown through the para-sympathetic branch which activates the pituitary gland and releases ACTH into the blood stream. ATCH causes the adrenal cortex to enlarge and release cortisol - this can then weaken the immune system.
Sympathetic Nervous System (Defining the concept) The sympathetic nervous system is a “subdivision of the autonomic nervous system responsible for arousing the body and mobilizing its energy during times of stress; also called the ‘fight-or-flight’ system.” In other words, it’s an automatic, innate response that causes the body to use its energy in a stressful situation to either fight or flee from danger. The sympathetic nervous system stems from the autonomic nervous system, which is responsible for involuntary functions, for example heart rate and digestion. It’s then subdivided into the sympathetic nervous system, which arouses the body, and the parasympathetic nervous system, which calms the body. However, the autonomic nervous system branches from the peripheral nervous system. The PNS carries information to and from the central nervous system.