Human Embryology and Developmental Biology, Case Study Example

Structure and function of organs responsible for End stage renal disease, respiratory failure, and pneumonia

End Stage Renal Failure

The organs involved in end stage renal failure also known as chronic renal failure are a pair of kidneys. These are two bean shaped structures about 11–14 cm (4.3–5.5 in) long; 6 cm (2.4 in) in width and 4 cm (1.6 in) in thickness. They are located in the abdominal cavity of the human body. Precisely, the kidneys can be found within the paravertebral gutter lying in a succinct retroperitoneal position forming a distinct oblique angle. These organs lay on either side of the spine. Due to the liver’s asymmetrical alignment within this spared space the right side kidney hangs a bit lower than the left, which has a more medial angle than the right. Importantly the left kidney is at a vertical level (Bard, Vize & Woolf, 2003).

Further descriptions of the kidney structure reveal that these bean shaped organ substance is responsible for its function. They are the renal cortex and medulla. Together these are called the parenchyma. Within the parenchyma are blood vessels. They adopt a 8 to 18 cone-shaped renal lobes, containing renal cortex encasing the medulla to create the renal pyramid. Renal columns are formulated aroundthe pyramids. Urine-producing vessels/nephrons extend over the cortex and medulla kidney surface.The renal corpuscles, tubules can be found in nephrons. These vessels pass from the superficial cortex into the deep sunken medullary pyramids, which are ultimately formed into a medullary that tunnels into a single duct collection mechanism (Boron, 2004).

Apart from secreting urine the main functions of the kidneys include excretion of waste; reabsorption of nutrients; promoting acid base balance; regulating osmolality in the body; maintaining normal blood pressure levels; secreting hemoglobin level maintenance hormones; responsible for calculating the filtration fraction along with providing renal clearance. End stage renal failure occurs when these functions are limited from extensive damage to the cortex or medulla of the kidneys (Bruce, 2004).

Respiratory failure

Respiratory failure occurs when there is inappropriate gas exchange within the respiratory system. The organ responsible for this process is the alveoli. In relation to this condition scientists differentiate it from vessels in other systems to classify them pulmonary alveoli. Pulmonary alveoli are specifically responsible for gas exchange within the lungs. Alveoli are hallow structures containing a lumen some 200 micrometers long, which expands during inhalation. Importantly, they can be found in thelung parenchyma or respiratory zone, where alveolar ducts and atria can be located. They form and terminate the respiratory tract, providing about 100 m surface area (Saladin, 2007).

Two human lungs contain about 700 million alveoli.An alveolus is covered by a 70% of its surface area with a capillary mesh, which makes up the epithelial and extracellular matrix surrounding these structures in the lung cavity.Collagen and elastic fibers also can be found in the structure of alveoli and the pores ofKohn, which facilitates stretching/expansion during gas exchange (Saladin, 2007).

Alveoli are the main respiratory human surface. These small air sacs emerge from bronchioles found in the lungs. Usually, an alveolus is a one-cellthick structure providingmoisture as well as immense surface area for gas exchange process. Capillaries filled with deoxygenated blood are taken from the pulmonary artery, which runs across a bunch of alveoli thin enough to cover the entire distance gases require for diffusion across its 2-cells thick membrane. When oxygen is inhaled it can be diffused through alveoli into the lung. Carbon dioxide is diffused outward from the lung. In respiratory failure alveoli function is grossly inadequate and there is extreme difficulty in breathing (Saladin, 2007).

Pneumonia

The body organs responsible for pneumonia are two pairs of lungs. Precisely, it is an inflammatory of the lung affecting the alveoli sacs mainly. Humans have two pairs of cone shaped lungs located in the thoracic cavity on either side of the heart. The apex reaches the first rib which is behind the clavicle, while the lung base is in alignment with the lowest rib bone that can be palpated. Importantly, a space separating the two lungs is called the mediastinum where the heart is located. Pneumonia affecting the lungs compromises function, which consists of two zones, a respiratory and conducting zone. There are three lobes in the right lung and two in the left.  Fissures separates lobes these(Rosenberger, 2008).

The conducting zone containsairways for transmitting air. These include trachea, bronchi, and alveoli, while therespiratory zone is responsible oxygen and carbon dioxide transportation and exchange within the bloodstream. Lungs have both conducting and the respiratory zone elements. In pneumonia bacteria, viruses or substances invade the lungs interrupting its conducting and respiratory function (Rosenberger, 2008).

Predominantly, three types of organisms can infiltrate lung cavity causing pneumonia to develop. They are bacteria being the most common, viruses and parasites. Each organism creates a peculiar altered physiology depending on the extent of damage created to the lung. However,since pneumonia predominantly manifests as inflammation of the alveoli gas exchange difficulty is the most common reaction to invading organisms (Rosenberger, 2008).

References

Bard, J. Vize, P., & Woolf, S. (2003). The kidney: from normal development to congenital disease. Boston: Academic Press

Boron, W. (2004). Medical Physiology: A Cellular And Molecular Approach. Elsevier/Saunders

Bruce, C. (2004). Human Embryology and Developmental Biology (3rd ed.). Saint Louis: Mosby.

Rosenberger, E. (2008).Structure and Function of the Lungs. Anatomy and physiology. Sciences 360.

Saladin, S. (2007). Anatomy and Physiology: the unity of form and function. New York: McGraw Hill