A good understanding of anatomy and physiology is the basis of all medicine. Without knowing how the body works, how it is made up and how it can go wrong, we cannot even begin to design effective treatments and interventions, including surgery or new pharmaceutical drugs.
The body has many different systems which help to maintain the body’s normal function. Three of these functions are; the cardiovascular system, respiratory system and the musculoskeletal system. In this assignment I will be looking at how these three systems work both at resting and during exercise.
Wilmore, J.H; Costill, D.L (2004) states that the cardiovascular system consists of; the heart, which acts as a pump, blood vessels acting as a system of channels and it also consists of blood which acts as a fluid medium.
The cardiovascular system has three main functions:
Transports oxygen and nutrients to the body’s cells and transports carbon dioxide and waste products from the body’s cells.
Protects the body from infection and loss of blood.
Helps to regulate pH balance of the body, body temperature and the balance of fluid.
(Plowman, A. S; Smith, D.L; 2010).
Below is a diagram which shows the circulation of the cardiovascular system.
(Image from http://agingresearch.buffalo.edu/…/chf_circulatory_system.jpg)
As the diagram above shows the heart pumps oxidized blood to the body so the nutrients can be distributed to the cells and remove the waste which is then returned to the heart and then into the lungs to be oxidized again to return to the body.
Response to Exercise
Exercise uses up a lot of energy, which the cells derive from oxidizing glucose. Both glucose and oxygen have to be delivered by the blood. This means that the heart has to work harder to pump more blood through the body. This means it has to beat faster in order to achieve a higher throughput. The cardiovascular system responds to exercise by increasing the activity level. The adrenal gland increases the production of the hormones adrenaline and nor adrenaline. These have direct effects on the heart. These hormones cause an increase in the heart rate and the force with which the heart contracts each beat. This increases the total amount of blood that is circulated in the body every minute. That increase in blood circulation is required to meet the increased demand for nutrients and oxygen that the muscles and other tissues.
There are several types of exercise and they all affect the cardiovascular system in a similar way, an example of some of these are; short term light to sub maximal aerobic, long term moderate to heavy sub maximal aerobic, incremental aerobic, static exercise and resistance exercise. For the purpose of this essay I will be looking at and comparing; short term to sub maximal aerobic exercise and heavy sub maximal aerobic exercise and how they affect the cardiovascular system.
This image shows the graphs of the changes in the cardiovascular system during light exercise (left) and moderate to heavy exercise (right).
(Image from Plowman & Smith, 2010, (Image from Plowman & Smith, 2010
page 357. Figure 12.1) page 360. Figure 12.4)
The two images above contain graphs which show the changes in certain elements of the cardiovascular system; Q, SV, BP, TPR, HR and RPP. As the graphs show there is an increase in Q, SV, SBP, MAP, HR and RPP, this is due to the increase in heart activity. These changes occur in conjunction with the type of exercise, the more intense the exercise, the more these factors increase.
There are some differences in these graphs, these include; a dip in SBP and SV in the moderate to heavy exercise. The dip in the SV after around 40 minutes is caused by ‘thermoregulatory stress, which results in vasodilation, plasma loss and redirection in blood to cutaneous vessels to dissipate heat.’ (Plowman et al 2010:360) These reactions cause a reduction in venous return which then in turn affects the SV.
The dip in SBP is caused by a ‘continued vasodilation and a resultant decrease of resistance’ (Ekelund and Holmgren, 1967). During exercise the blood vessels continue to vasodilate in order to help the flow of blood to and from the heart.
During exercise there is an increase in TPR. This is because there is a vasodilation of the blood vessels to increase the blood flow to help increase the circulation of blood. Another reason as to why there is a decrease is to prevent a dramatic increase of MAP.
Plowman et al (2010) specifies that the DBP in these graphs does not change due to an intra-arterially measured BP. Also due to the small increase in SBP and no change in the DBP this causes the MAP to only increase slightly.
Image showing the distribution of blood to different parts of the body during short term, light to moderate exercise.
(Image from Plowman & Smith, 2010, page)
Image showing the distribution of blood during long term, moderate to heavy exercise.
(Image from Plowman & Smith 2010)
As the two images show above the distribution of blood during the two different types of exercise, it shows that as the intensity of the exercise increases the amount of blood to the musculoskeletal system and the skin increases. With this increase of blood to the musculoskeletal system and the skin means that other areas of the body have less blood available to them.
The increase in blood supply to the musculoskeletal system and the skin is in order to help cope with the demand from these systems for more oxygen (energy) to help them perform the exercise, as they are the systems used during exercise.
Measuring & Assessing the Cardiovascular System
The respiratory system is a series of organs designed to facilitate the exchange of gases, mainly oxygen and carbon dioxide, between red blood cells in the circulatory system and the body’s cells. The cells in the body require a constant supply of oxygen (O2) and the ability to ventilate carbon dioxide (CO2) produced by the cells away from them (Wesson, K Thompson, G., Wiggins-James, N. & Hartigan, S. 2005).
The respiratory system is important because body needs energy to function during the day and during exercise, the majority of this energy is provided by the respiratory system via oxygen. This is done by the respiratory system via respiration. Below is a diagram of the respiratory system.
(Image from http://www.umm.edu/respiratory/anatomy.htm)
There are four main components of respiration which are described by Plowman et al (2010) as:
Pulmonary Ventilation – process where air is moved in and out of the lungs via the nose and mouth.
External Respiration – exchange of gases between blood and lungs.
Internal Respiration – exchange of gases between blood and the tissues at cellular level.
Cellular Respiration – the cells using the oxygen in order to produce energy.
Respiratory Systems Response to Exercise
During exercise muscles have a massive need for energy (oxygen) and the removal of waste products such as carbon dioxide is met by the respiratory system (Wilmore et al 2004). This means that the breathing rate and breathing depth increases although the inspiratory reserve volume and expiratory reserve system decreases. The increases slowly start to happen just before exercising. This is because the ‘anticipation rise’ releases hormones like adrenaline this then stimulates the respiratory system. It then has a heavy rise during the exercise which is caused by the nervous system. Once exercising just before the maximum for awhile the ventalisation begins to slow down to a steady rate. Although at the maximum exercise the ventalisation will continue to increase until the exercise has finally stopped.
The musculoskeletal system is an organ system that enables people the ability to move using the muscular and skeletal systems. The musculoskeletal system provides form, support, stability, and movement to the body. It is made up of two systems; skeletal and muscle. Below is an image which shows these two systems, from an anterior prospect, the muscular system is on the left and the skeletal system is on the right.
(Image from http://www.whitemountainpt.com/html/faqs.html)
The skeletal system provides a type of framework for the muscular system and organs of the body and is made up of bones and cartilage. A healthy skeletal system is important to prevent any injuries from happening whether it is sports related or just general, injuries to this system can affect the muscular skeletal system as well as organs.
The skeletal system has a number of functions, these include:
Protection – The skeleton protects vital organs in the body. E.g.:
The Ribs, Spine and Sternum protect the lungs and heart.
The skull protects the brain, eyes, the middle and inner ears.
The scapula and clavicle protect the shoulder.
The tarsals and carpals protect the wrist and ankle.
Movement – The muscles are attached to the skeleton by tendons and without the skeleton to give leverage, the movement of the body would be very restricted.
Shape & Protection – The body’s shape comes from the skeleton as it supports the body and maintains its shape.
Blood Cell Production – The generation of blood cells is started in the skeleton. The blood cells are produced in the red bone marrow of the bones.
Storage – The bone matrix stores calcium and the bone marrow can store iron in ferritin.
Osseous tissue is constantly undergoing change because it is a living tissue. Plowman et al (2010) states that
The human skeleton can be split into two major subdivisions; the appendicular skeleton and the axial skeleton.
The appendicular skeleton joins with the axial skeleton at the shoulders and hips. Forming a loose attachment with the sternum is the pectoral girdle, or shoulder. The appendicular skeleton consists of 126 bones and makes the body movement possible. The appendicular system protects the organs of digestion, reproduction and excretion. The bones in the appendicular system are either; long or short bones. These bones include those in the arms, legs, feet and pelvic girdle.
The axial skeleton is the central framework for the body and consists of 80 bones. It has five main components: Vertebral Column, Cranium and facial bones, Thorax, Auditory Ossicles, Ribs. The bones in the axial system are either flat or irregular shaped bones and these bones protect the body’s vital organs, i.e. heart and lungs.
Skeletal Muscle System
There are different types of muscle which perform different tasks within the body. These types of muscle are:
Smooth Muscle – this type of muscle is found in the digestive system and blood vessels, this type of muscle is involuntary.
Cardiac Muscle – this type of muscle is found in the heart and is also controlled involuntarily.
Skeletal Muscle – this type of muscle is found on the muscles that are attached to the skeleton to cause movement of the body. These muscles are voluntary.
Below is an image which shows these types of muscles and what their individual fibres look like.
(Image from http://graphics8.nytimes.com/images/2007/08/01/health/adam/19917.jpg)
The skeletal muscles in the body are responsible for all the movements which occur. These movements occur by the skeletal muscle contracting using energy from the ATP system, although for muscles to perform effectively the other systems in the body such as the respiratory, cardiovascular and endocrine must be working effectively.
There are ‘unique characteristics of muscle tissue’ [which are] ‘specifically suited to its primary function: converting an electrical signal into a mechanical event (contraction of muscle fibres).’ (Plowman et al 2010:513).
These characteristics, which are also described by Plowman et al (2010), are:
Skeletal Muscle during Exercise