Human Biology


Human biology is adisciplinary that examines humans through influences and interplay ofmany fields. This study helps to understand the human body bettermaking it easier to understand issues connected to the body. Humanbiology enables us to study the human body and its systems that worktogether to keep the body in the balance. The system revolves aroundthe nervous system, immune system, and circulatory system. Thecirculatory system ensures that the body is getting enough oxygen tokeep the body cells alive. It also ensures that the blood vessel isfunctioning well. Also, it is also the branch of biology that dealswith body immunology which is the different ways in which the bodyfights and protects itself from harmful pathogens.

Thrombocytopeniais a condition where the body has low platelet count. Low plateletcount has many symptoms occurring. For instance, the bleeding time islengthy. Bleeding may vary from mild to serious. It can also bebleeding from the underneath the skin or the surface. Mildthrombocytosis signs are found in the blood test. Severe bleeding isheavy bleeding in the intestines or brain. Low platelets that arebetween (20-50) one bruises easily and bleeds longer when they cutthemselves. In the case of very low platelets count (10-20) onebruises more quickly and when they cut themselves they bleeds longereven with no clear cause. Extremely low platelets that are below 10one is at risk of bleeding without obvious cause. When the plateletsare low, one notice various types of bleeding such as blood in urine,nosebleeds, gum bleeding, bleeding from the bowel which can be bloodin the stool or black stool. The virginal bleeding especially a heavymenstrual circle is also another type of bleeding. Black or purplespots on the skin or lips may also be a sign of easy bruising. Thesespots appear temporary when platelets are low. [ CITATION Raj12 l 1033 ]

&nbspHomeostaticControl Mechanisms are devices for re-establishing homeostasis. Indefinition, homeostasis refers to the situation in which an organismtends to adjust its internal environment and maintaining equilibrium,by use of feedback control systems. There are two types of feedbackcontrol systems, positive and negative. Positive feedback systemsenhance the original stimulus. For example, during childbirthoxytocin is released to speed up contractions. The increase incontractions leads increased release of oxytocin the cycle goes onbirth occurs. Positive feedback ends at birth when the release ofoxytocin stops.&nbspNegativeFeedback Control Systems are inhibitory. They object a challengingsituation through creating the response which is opposite to theinitial disturbance. Besides, they create opposite action to thechange used to activate the system. Negative feedback plays a vitalrole in maintaining the internal environment constantly. They alsorestrict variables from straying too far outside of their normalrange.[ CITATION Wol11 l 1033 ]

Erythropoietinis a hormone that is produced by the kidney when the kidneys receiveless oxygen. In response, Red blood cells are made by the bonemarrow. The manufactured red blood cells enable more oxygen andhemoglobin to be carried. When a homeostatic condition gets achieved,the release of the hormone stops this is therefore, a negativefeedback mechanism as, as soon the homeostatic state is achieved, therelease of the hormone stops.[ CITATION Sof11 l 1033 ]

Tobaccocontains nicotine which is a vasoconstrictor. This means that bloodvessels reduce in diameter. Nicotine causes the arteries to becomenarrow due to the gradual buildup of fatty materials within theirwalls. It also leads to increased level of fibrinogen and increasesplatelet aggression making the blood stickier. Arteries have a smoothinner lining which is very susceptible to damage from nicotinesmoking. Nicotine diminishes the ability of the arteries to preventblockages. This leads to the formation of plate deposits on theruined areas of the arteries making it form dangerous blood clots.[ CITATION Wor13 l 1033 ]

Whensmokers are actively smoking, rapid sympathetic responses raise bloodpressure levels. As the arteries vasoconstrictors and the bloodbecome stickier, the force of blood pushing against the walls of thearteries as the heart pump increases, hence high blood pressure. Theincreased blood pressure is due toxic effects of nicotine. Increasedcarbon monoxide affects the structure of arteries making the bloodpressure to reverse. Also, nicotine stimulates the production ofadrenaline hormone which leads to high blood pressure.[ CITATION FAb15 l 1033 ]

The blood vesselcaptured by Shirelle shows to be branching. Red blood cells areclearly visible, meaning the blood vessel is carrying oxygenatedblood. Red blood cells match single file, and the wall is too thin,(endothelial wall) with pores visible. From the above observations,the blood vessel captured is a capillary. Capillaries bringoxygenated blood and carry away deoxygenated blood. They have fragilewalls to allow substances easily diffuse through them and containpores to allow selective molecules pass through them,


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