Circulatory System

The circulatory system often referred to as the cardiovascular system is responsible to pump and transport blood, nutrients, hormones, and gaseous exchange throughout the body and lungs. The heart, network of veins, arteries, and capillaries together referred to as blood vessels, and blood made up of blood, plasma, and platelets make up the circulatory system. Also, the heart is responsible for removing damaged tissues and cells (Cleveland Clinic , 2021).

 

Fig: Diagram representing different components of circulatory.

Source: (BCcampus, 2022)

The circulation system works by pumping blood between lungs and body parts, and this process is called circulation. The lung transports oxygen-rich blood to various parts and receives carbon dioxide-laden blood from other body parts, on its way the blood carries nutrients to various body parts and while returning takes degraded cells and tissues with it. Based on its route the circulation of blood is studied in form of 3 types of circulation: Pulmonary circulation and Systemic circulation, and Coronary Circulation (Peate & Nair, 2016). Pulmonary and systemic circulation together are referred to as Double circulation.

Pulmonary Circulation: It involves the passage of deoxygenated blood from right ventricle of the heart to the lungs and then returns the oxygenated blood from the lungs to the left atrium of the heart (Peate & Nair, 2016). The right and left pulmonary arteries take the blood to heart so as to facilitate the exchange of gases.

Systemic Circulation: it involves the passage of oxygenated blood from the left ventricle of the heart to other parts of the body and deoxygenated blood from various organs of the body to the right atrium of the heart (Peate & Nair, 2016). The systemic arteries transport oxygenated blood from the heart to various organs of the body and this facilitates the exchange of nutrients throughout the body.

Significance of Circulation:

• Helps in transportation and supply of hormones, oxygen, essential nutrients, and essential elements to various organs and parts of the body
• Helps to maintain body temperature.
• Prevents intravascular coagulation.
• Helps to carry waste products to the site of excretion.

 

Fig: Diagram representing Pulmonary circulation and Systemic circulation.

   Source: (Toppr, 2022)

The Heart:

The heart is a fist-sized muscular organ whose major function is to pump the blood throughout the body with the help of a vast network of blood vessels. It is located between the lungs, behind and slightly left of the breastbone (Peate & Nair, 2016).  

Features of heart: Size-12 cm from base to apex

   Shape- Conical

   Weight- 250gm in female, 300gm in male

The heart is supported by a strong system of muscular walls (myocardium), the endocardium on the inside, and the pericardium on the outside. The heart cavity is divided into 4 chambers the two upper chambers are called atria and the two lower chambers are called ventricles (Peate & Nair, 2016).

Circulation

 

Fig: Structure of a human heart

Source: (Britannica, 2022)

Working of the heart ( Iaizzo, 2015):

• The left atrium receives blood rich in oxygen from the lungs through pulmonary veins and pumps it to the left ventricle by crossing bicuspid valves.
• The left ventricle is responsible to transport blood to the various parts of the body.
• The right atrium obtains deoxygenated blood from the veins (superior venacava) and pumps it to the right ventricle by crossing the tricuspid valve.
• The right ventricle obtains blood from the right atrium and pumps it to the lungs for oxygenation (pulmonary artery).
• In the lungs venous blood comes in contact with inhaled air and exchanges oxygen for carbon dioxide.
• Blood pressure is observed to be the highest in the left ventricle and in the aorta and its arterial branches as they are responsible for the transportation of blood to all the body parts(Lawton, 2020).

Heartbeat is caused by contraction and relaxation of the myocardium ( Iaizzo, 2015). These contractions are stimulated by an electrical stimulation generated from the S-A node, positioned in the right atrium. The stimulation causes the atrium to contract which forces the blood into the ventricle. Further when the ventricle contracts, the atria start to relax and blood tends to flow back into the atria but are stopped by the closing of the bicuspid and tricuspid valve and hence producing the sound. The contraction phase is referred to as systole while the relaxation phase is known as the diastole, and the process is called the cardiac cycle ( Iaizzo, 2015).

Blood:

The blood is a circulating fluid composed of blood corpuscles (45%) and plasma (55%). It is the main component of the circulator system as it connects the heart to other parts of the body. It is responsible to transport oxygen, hormones, and nutrients throughout the body.

 

Functions of Blood ( Iaizzo, 2015):

• Transportation of oxygen and carbon dioxide.
• Transportation of nutrients
• Transportation and facilitation of excretion of metabolic waste.
• Regulates body temperature
• WBC protects from pathogens.
• Maintains electrolyte balance.

The fluid portion of blood is referred to as plasma. It is the portion of the blood in which the erythrocytes, leukocytes, and platelets are suspended. It is responsible for maintaining colloidal osmotic pressure, and coagulation of blood.

The vast network of blood vessels is responsible to deliver blood to various parts of the body. Types of blood vessels (Cleveland Clinic , 2022):

Arteries: Carry oxygen-rich blood away from the heart. Handle a large amount of blood pressure but carry only 10-15% blood volume out of total. They are strong, muscular, with thick walls and narrow lumen

Arterioles: Arteries branch into smaller versions called arterioles (continuation of arteries). They get bigger or smaller to control blood pressure.

Capillaries: these are tiny vessels that have thin walls. These are responsible for the transportation of oxygen and nutrients from the blood to the tissues and organs. They also take the waste products from the tissues.

Venules: these are tiny vessels (continuation of veins) and get larger near the heart. They receive blood from the capillaries and take them to the larger veins (Cleveland Clinic , 2021).

Veins: They carry blood toward the heart and carry a large amount of blood (75%) but do not handle high blood pressure. They have a thin less muscular wall with a big lumen.

 

Fig: different types of blood vessels

Source: (Lawton, 2020)

• The range of heart rate should be between 60-100 beats per minute with relaxation of 50-70 beats as normal(Lawton, 2020).
• The blood pressure level should be 120/80 mm Hg with relaxation to 130/90 as normal.
• When the heart is working efficiently the person does not feel tired soon
• A healthy level of blood cholesterol level is important to perform basic functions of the body(Lawton, 2020).
• The ability to quickly return to the normal heart rate and breathe properly after strenuous exercise.
• Blood vessels have no constrictions and blood flow is smooth.
• Fast rate of coagulation at the spot of bleeding

Components of the Circulatory System

Some of the unhealthy conditions of circulatory system are listed below:

• Atherosclerosis: Stiffening of arteries due to high levels of cholesterol( Iaizzo, 2015).
• Hypertension: Clinical condition of sustained blood pressure level above 130/90mmHg
• Hypotension: Clinical condition of sustained blood pressure level below 120/80 mmHg.
• Myocardial infarction: also called as heart attack, is the condition when the supply of blood to the heart is hindered.
• Mitral Stenosis: When the mitral valve is abnormally narrow which prevents the smooth blood flow through it.
• Arrhythmia: Abnormal heart rates. Increased heart rates (tachycardia), and decreased heart rate (bradycardia)(Peate & Nair, 2016).  
• Angina pectoris: Pain in the chest due to less oxygen supply to the heart.
• Stroke: Occurs when one of the vessels leading to the brain is either blocked or gets collapsed(Lawton, 2020).

Cardiovascular diseases include the abnormal conditions of the heart and blood vessels carrying blood, and these are related to many dermatological manifestations. Cardiovascular diseases show their symptoms on the skin, which include swelling of feet and lower legs, blue or purple colour or net-like pattern on skin, reddish or purplish lines under the nails, clusters of waxy bumps on the skin. These cutaneous diseases are often used to diagnose certain heart conditions (Gallitano, 2019).

 

Fig: Skin with waxy bumps

Source: (American Academy of Dermatology Association, 2022) 

Skin manifestations occurring due to cardiovascular disease:

Certain congenital cardiac defects have shown their effect on skin. For example, coarctation of aorta associated with turner’s syndrome shows its effect on skin.

Studies have shown that consistent hypertension leads to wrinkles on the skin.

• Popliteal Entrapment syndrome: In this condition the muscles and tendons near the knee narrow down the popliteal artery due to which blood flow to the lower leg is restricted(Cleveland Clinic logo, 2022).
• Raynaud’s Phenomenon:  Frequent spasms of arteries of fingers and toes on exposure to cold or stress.
• Blood clots formed inside the blood vessels leads to bulges on the skin, swollen area, or red or purple pigmentation near the knee, thighs, or calves.
• The entry of the COVID-19 virus into the body triggers the accumulation of Angiotensin-converting enzyme 2. The Angiotensin II excess leads to vasoconstriction, decrease vascular permeability, and abnormal myocardial remodelling. This condition leads to the formation of vascular lesions on the skin of the affected people(Duong, Bouaziz, Jachiet, & Velter, 220).
• Eczema is a condition of the skin characterized by swelling, dryness, itchy skin and rashes. It occurs when the blood supply to the skin is restricted leading to decreased supply of oxygen(Ascott, et al., 2019).
• Xanthoma: these are the deposits of lipids found on the skin of patients with hyperlipidemia.
• Systemic Amyloidosis: Amyloid deposits in the blood vessels and heart leads to the formation of purple stains on the skin referred to as pinch purpura.         

           

Fig: Systemic Amyloidosis Fig: Xanthoma

Source: (Tschen, 2016) Source: (Tschen, 2016)

• Arterial ulcers: It is the result of vascular insufficiency, and is characterised by acute pain and circumscribed appearance near the affected area(Tschen, 2016).
• Emboli: embolic lesions in the skin can lead to the formation of distal infarcts. They are mostly seen in cardiovascular patients after catheterization or after use of anticoagulants
• Calciphylaxis: It is the condition of decreased vascular calcification and thrombosis of vascular cells. They appear as large purple area on the skin(Tschen, 2016).
• Livedo reticularis: it is the condition of vascular congestion which produces a reticulated pattern on the skin. It is observed mostly on the legs and is a condition of hyperpigmentation.
• Psoriasis: it is a skin condition occurring due to inflammation and hyperproliferation of epidermis due to the formation of plaque near knee and elbows. Inflammation in the dermis is caused by infiltration of lymphocytes(Giang, et al., 2018).

             

   Fig: Arterial ulcers          Fig: Emboli

   Source: (Tschen, 2016)          Source: (Tschen, 2016)

• Maintain a healthy body weight, as high fat concentration of fat in abdominal region or chest region, will lead to cardiovascular diseases(World Health Organisation, 14).
• Eating a healthy diet i.e., low in trans-fat and cholesterol add more fruits, vegetables, and legumes to the diet.
• Increase the physical activity to 2.5 hours per week. this is because physical activity helps to improve blood pressure, cholesterol levels and also control body weight(World Health Organisation, 14).
• Tobacco and alcohol consumption should be avoided.
• Managing diabetes is also essential, as diabetes increases the chances of many cardiovascular disorders and mainly hypertension and can cause clogging of blood vessels(Medline Plus, 2021).
• Blood pressure and blood sugar levels should be checked regularly
• Manage stress as stress conditions lead to high blood pressure and sometimes can even trigger heart attacks(Medline Plus, 2021).

Circulatory system is one of the most significant systems of the body as it connects the whole body. Respiratory system is dependent on blood to transport oxygen, endocrine system is dependent on blood to transport hormones t its target organ, digestive system is dependent to transport nutrients and excretory to transport waste material to the site of excretion. All these are interconnected with the help of strong vast network of blood vessels. A healthy cardiovascular system is essential for maintain a healthy life. Several heart related disorders lead to death. The paper has explained anatomy in as detailed manner as possible, and is supported with diagrams and images for better understanding.

The main infestations of cardiovascular diseases on skin are found due to constriction of vessels or restricted flow of blood and oxygen to the skin. The plasma proteins help in immune process, and the inflammatory response is also attributed to the inflow of plasma proteins. It was found that many cardiovascular diseases and their effect on the skin is due to increased levels of fat and cholesterol in the blood. Cardiovascular diseases can lead to difficulty in breathing. The most common disorder of the circulatory system is hypertension, and most common in adults. This condition leads to early wrinkling of the skin, especially in females. Many of the skin conditions occurring due to the disturbed cardiovascular system are listed and explained in brief and some are supported with images.

Healthy or Unhealthy Circulatory System

The WHO has suggested that the key to a healthy cardiovascular system lies in maintaining a healthy body weight and a low-fat diet. Individuals should be aware enough to regularly check their blood pressure, blood sugar levels, and also maintain stress levels. Diabetic patients need to maintain an optimum blood glucose level in order to maintain a healthy heart. Hence from the research, it can be concluded that a healthy cardiovascular system can be maintained by following a healthy lifestyle, reducing fat in the diet, and proper exercise.

References

Iaizzo, P. A. (2015). Handbook of Cardiac Anatomy, Physiology, and Devices. Germany: Springer International Publishing.

Adobe Stock. (2022, March 28). The human circulatory system. Blood vessels anatomy. Cross section of vessels: aorta, elastic artery, muscular artery, arterioles, capillaries, venules and veins. Retrieved from The human circulatory system. Blood vessels anatomy. Cross section of vessels: aorta, elastic artery, muscular artery, arterioles, capillaries, venules and veins.: https://stock.adobe.com/in/images/the-human-circulatory-system-blood-vessels-anatomy-cross-section-of-vessels-aorta-elastic-artery-muscular-artery-arterioles-capillaries-venules-and-veins-vector-illustration-in-a-flat-style/296877235

American Academy of Dermatology Association. (2022, March 28). Heart Disease: 12 Warning Signs that Appear on your Skin. Retrieved from American Academy of Dermatology Association: https://www.aad.org/public/diseases/a-z/heart-disease-warning-signs

Ascott, A., Mulick, A., Prieto-Merino, D., Schmidt, M., Abuabara, K., & Smeeth, L. (2019). Atopic eczema and major cardiovascular outcomes: A systematic review and meta-analysis of population-based studies. The Journal of allergy and clinical immunology, 143(5), 18211829.

BCcampus. (2022). The circulatory system. Retrieved from BCcampus: https://pressbooks.bccampus.ca/nutr1100/chapter/the-cardiovascular-system/

Britannica. (2022, March 28). Heart Anatomy. Retrieved from Britannica: https://www.britannica.com/science/heart

Cleveland Clinic . (2021). Circulatory System. Retrieved from Cleveland Clinic : https://my.clevelandclinic.org/health/body/21775-circulatory-system#:~:text=The%20circulatory%20system%20(cardiovascular%20system,start%20the%20circulation%20process%20over.

Cleveland Clinic . (2022). Blood Vessels. Retrieved from Cleveland Clinic : https://my.clevelandclinic.org/health/body/21640-blood-vessels#:~:text=Blood%20vessels%20are%20channels%20that,60%2C000%20miles%20of%20blood%20vessels.

Cleveland Clinic logo. (2022, March 28). Vascular Disease. Retrieved from Cleveland Clinic logo: https://my.clevelandclinic.org/health/diseases/17604-vascular-disease

Duong, T., Bouaziz, J. D., Jachiet, M. M., & Velter, C. (220). Vascular skin symptoms in COVID-19: a french observational study. J Eur Acad Dermatol Venereol, 34(9), e451-e452.

Gallitano, S. M. (2019, October 17). Dermatologic Manifestations of Cardiac Disease. Retrieved from Medscape: https://emedicine.medscape.com/article/1094269-overview#a1

Giang, J., Seelen, M. A., van Doorn, M., Rissmann, R., Prens, E. P., & Damman, J. (2018). Complement activation in inflammatory skin diseases. Frontiers in immunology, 639.

Lawton, C. M. (2020). The Human Circulatory System. United States: Cavendish Square Publishing LLC.

Medline Plus. (2021, December 3). How to Prevent Heart Disease. Retrieved from Medline Plus: https://medlineplus.gov/howtopreventheartdisease.html

Peate, I., & Nair, M. (2016). Fundamentals of Anatomy and Physiology: For Nursing and Healthcare Students. United Kingdom: Wiley.

Toppr. (2022). Types of blood circulation. Retrieved from Toppr: https://www.toppr.com/ask/content/concept/types-of-blood-circulation-201046/

Tschen, J. A. (2016). Points To Remember: The Skin in the Cardiovascular Patient. Methodist DeBakey Heart & Vascular Center, 12(1), 65-69.

World Health Organisation. (14, February 2020). How to take care of your heart health. Retrieved from World Health Organisation: https://www.who.int/philippines/news/feature-stories/detail/how-to-take-care-of-your-heart-health