Role Of Energy, Body Systems, And Homeostasis In Human Physiology

Anabolism

Q1, Discuss role of energy in the body

• Provide definitions of the phrases: anabolism; catabolism & metabolism

• Discuss the role of energy in the body (why does body need energy? Talk about MRSGREN)

• Describe how energy is produced in mitochondria.

Q2, Analyse how two body systems interrelate to perform a named function / functions

• Roles of cardiovascular, respiratory and digestive systems

o Analyse the functions of cardiovascular system (transport of gases; nutrients – proteins; fats & glucose); respiratory (gases exchange O2/CO2) and digestive system (producing glucose). Explain how glucose and oxygen is transferred to mitochondria when energy is produced.

Glucose + Oxygen = Energy + carbon dioxide + water

H12C6O6 + 6O2 = 36 ATP +6 CO2 +6 H2O

Analyse the equation

Q3 Discuss the problem homeostatic responses to changes in the internal environment during exercise

• Definition of homeostatic

• Internal environment

• Concept of negative feedback as regulatory mechanism

Homeostatic mechanisms for regulations of

1. Heart rate: roles of internal receptors, autonomic nervous system sympathetic and parasympathetic nerve supply, cardiac centre, sinoatrial node; effective of increased body temperature and adrenaline of heart rate

2. Breathing rate: role of internal receptors, autonomic nervous system – sympathetic and parasympathetic nerve supply, respiratory centre, diaphragm and intercostal muscle

3. Body temperature: production of heart by the body, e.g. through metabolic processes; loss of heart by the body – radiation, conduction, convection, evaporation; role of hypothalamus, autonomic nervous system – sympathetic and parasympathetic, skin – role of arterioles and sweat glands; effective of shivering; implication of surface area to volume ratio, e.g. in care of babies; fever

4. Blood glucose levels: roles of pancreas, liver, insulin, glucagon, Discuss the role of insulin & glucagon in balancing glucose level in human body.

Q4 Evaluate the importance of homeostatic in maintaining the healthy functioning of the body.

• What happens if heart rate; breathing rate; body temperature and glucose level go up and down for long period of time

• Evaluate different diseases (e.g. heart disease; lung diseases or diabetes as part of imbalance of homeostatic mechanisms)

Anabolism

Anabolism is a set of metabolic procedures, which are involved in constructing the larger molecules from the smaller units of molecules. All the anabolism mechanisms require energy for producing bonds between the smaller molecules. The anabolic reactions are powered by the energy gained from the hydrolysis of ATP^[1]. In human and other living organisms’ body, these types of reactions tend to build up organs or tissues.

Catabolism is the metabolic procedure functions opposite to the anabolic procedures. In this process, larger molecules are broken down through a number of processes to obtain smaller unit. In contrast to anabolic reactions, the smaller unit produced in the processes are oxidized to produce energy or used up in other anabolic processes. This procedure mainly provides energy to body^[2].

Metabolism is a group of chemical transformation related reactions in the living organism’s cells. The metabolic reaction helps organisms to undergo growth and reproductive procedures in response to the external and internal environment. Metabolism is divided in two types of procedures including catabolism and anabolism^[3].

Catabolism

Energy is the key of individual’s daily living. A living organism needs energy at every moment of life, from movement to metabolism and nutrition. The MRS GREN is the basic body functions of the living organism, all of which needs energy. Movement is essential for animals to collect food and transport for sake of survival. Energy is produced from burning carbohydrate or fat stored in muscles, making individual t move. Respiration is the process of conversion of energy from the carbohydrates and fats and the energy produced by this method is used up by cells. Sensitivity is another process of responding to the external stimuli, it is also done by energy, as it is required to send signals from brain to muscle to function against stimuli^[4]. Growth is essential for survival, which is powered by usage of energy, construction of building blocks of body needs hydrolysis of ATP (energy) to proceed with growth reactions. The next step of growth is reproduction, which also needs huge amount of energy, the HPG system and the oxidizable metabolic fuels power mechanisms related to control of sex behavior. Like the above methods, the excretion and nutrition are also entirely dependent upon energy consumption. Each step of these procedures needs energy^[5]. 

Mitochondrion is the cell organelle resides in all eukaryotic cells and it is responsible for performing aerobic respiration, through which ATP from the nutrients is generated by the use of oxygen. The energy is generated through three critical process constituting glycolysis, kreb’s cycle and electron transport chain (ETC). kreb’s cycle enzymes and ETC components resides in mitochondria. Through glycolysis, glucose is spit into pyruate while generating ATP and NADH. Pyruvate is converted to acetyl-CoA, which provides ATP, FADH2 and NADH through Kreb’s cycle. NADH and FADH2 carries electron to ETC and through the proton pumping proteins in the inner membrane protons are pumps out to the inter-membrane space creating a gradiant. This gradiant serves for ATP synthesis by the inner-matrix protein ATP-synthase^[6].

The cardiovascular system is one of the most important systems in pumping blood through the vessels for transporting oxygen and nutrients to cells. During the period of inhalation, air enters lung and oxygen is absorbed through the lung membrane into the bloodstream. The oxygen-rich blood is pumped through heart and blood vessels and capillaries. These capillaries linked to each cell provide oxygen to cell and collect carbon dioxide produced by cells and bring it back to lung. Another critical function is to supply nutrients to cell. After ingestion of food, the digested food migrates to intestine from where it is absorbed in bloodstream. Additionally, glucose is absorbed from liver and blood transports nutrients and glucose to each cell through the similar process and removes waste materials from cells^[7].

Gas exchange is the most important function of respiratory system. The oxygen inhaled through nose reaches to alveoli of lung, the alveoli of lung and blood capillaries are very close to contact and oxygen can quickly diffuse through the wall of alveoli to the blood capillaries, similarly carbon dioxide diffuses from capillary to alveoli. After entering into blood stream oxygen is captured by RBCs and then oxygenated blood goes to left part of lung and from where it is pumped through the rest of the body and oxygen-deficient, carbon-dioxide rich blood goes to right side of lung^[8].

Metabolism

The major role of digestive system is to digest the consumed food and assimilation of the nutrients from the digested foods to produce energy for regular activity. The digestive system starts from the mouth and ends to the beginning of excretion system. The organs in the digestive tract contain glucose and it is the smallest sugar unit, which is obtained through the hydrolysis of larger molecules by the digestive enzymes in digestive system. In small intestine, glucose is being absorbed and carried to liver through bloodstream and stored for providing energy in future^[9].

Glucose + Oxygen = Energy + carbon dioxide + water

H₁₂C₆O₆ + 6O₂ = 36 ATP +6 CO₂ +6 H₂O

In the above equation, from glucose and oxygen, energy, carbon dioxide and water is produced and the process is known as respiration. This is the process of aerobic respiration; glucose is obtained through the digestion of consumed food. Glucose undergoes glycolysis in cell cytoplasm and produces pyruvate^[10]. Pyruvate is converted to acetyl CoA by PDC complex and transported to mitochondria through transporter and enters into krebs cycle. On the other hand oxygen is diffused through the mitochondrial membrane pores and serves as an electron  acceptor in the electron transport chain. The equation of respiration is depicting the way how body gains energy. The glucose obtained from glucose breakdown and oxygen obtained from breathing are used by body to produce energy. The by-products of the reaction include carbon dioxide and water, which are exhaled^[11].

Definition of Homeostatic and internal environment

Homeostasis is a property of a system where variable of the system are regulated for maintaining the internal environment in stable condition. Human body is a complex organism including different variables which are functioning to keep a well-established balance in the system. In this context, the internal environment is referred to the condition prevailing within organism’s body and especially with respect to the composition of tissue fluids. There is a significant relation with homeostasis and internal environment of human body^[12].

The negative feedback is the reaction causing decrease in function. The biological system of human body sometimes provides negative feedback to some stimulus. Sometimes, output of the system is lessened. One example can be the human body temperature. The temperature fluctuations sometimes promote human hypothalamus to respond according to it. In temperature drop, body attempts to shivers to bring up temperature, in contrast body sweats to cool down for evaporation^[13].

Heart rate- The heart rate is being controlled by two systems, the sympathetic nervous system and parasympathetic nervous system. The sysmpathetic nervous system works during fear, sress or working of muscles.It enhances the heartbeat and rate. The aim is to manage good environment in internal organs to keep the heart rate good. The internal receptors drive message to brain and it drives the response to the cardiac centre through the nerve impulses. Through this action, nerve slows down heart rate and BP is decreased to normal rate. During fear or stress condition, adrenaline is released and it promotes heart rate to be faster through the boost up of sympathetic nervous system’s effect. Thus, while increasing heartbeat, it also starts to beat fast, like during the excess production of carbon dioxide, breathing rate enhances to get breathing back to normal homeostatic level.

Role of Energy in Body

Breathing rate- Breathing rate is also being regulated to keep the normal homeostatic balance. Breathing leads to the coordination of three complex interactions including respiratory control, sensory system and effector system. The respiratory control centre located ate human brain stem controls the breathing rate during day and night. The control centre endlessly monitors the oxygen and carbon dioxide level in the blood stream for adjusting the breathing rate for maintaining balance and body homeostasis. Mostly, the breathing rate is managed by medulla. The system is flexible^[14]. The action potential of breathing causes the contraction of muscle of diaphragm along with the intercostals muscle. Medulla is able to detect small change in pH and determine the amount of CO2 in blood. At low pH, respiratory centre is stirred and it enhances rate of breathing, in contrast high pH make breathing slower for decrease in stimulation of nervous system^[15].

Body temperature- The thermo-receptors in human skin are able to indicate the changes happening within the environmental temperatures. After detecting the changes, the autonomic nervous system sends signal to the hypothalamus. Then the hypothalamus reviews the temperature of blood and sends the nerve impulse in the posterior hypothalamus, which is the heat gain centre. This nerve impulse then sent to the effector, which is skin. Then a number of mechanisms happen for conserving heat^[16]. Vasoconstriction occurs when the shunt vessel widens to allow arterioles to become constrict, thereby reducing blood flow to capillary surface. Then blood flows through the insulating layer of adipose tissue, thereby preventing the dissipation of heat to environment^[17]. Shivering occurs, which helps to generate metabolic heat. Sweating is reduced and respiration is enhanced, the pilli erector muscles are motivated to raise hairs, thereby trapping insulating layer of air.

Blood glucose level- The regulation and homeostasis of blood glucose level is dependent upon different molecules, organs and cell types. The antagonistic pancreatic hormones, insulin and glucagon regulate the concentration of glucose. The glucose transporter receptors on alpha and beta cells detect glucose concentration in blood. The beta cell reacts against raised blood glucose level and secrete insulin hormone^[18]. Insulin signals body tissue to intake glucose or converting glucose to lipid or glycogen as storage of energy. During low glucose level, alpha cells activates and secretes glucagon hormone for stimulating skeletal muscle and liver for breakdown of glycogen in glucose and stimulates liver to produce glucose by breaking down glucose. It also helps to stimulate glucose formation from glycerol. In this way these two hormones plays their role to take glucose level back to normal rate^[19].

Effect of long-term fluctuation of breathing rate, heart rate, glucose level

The fluctuation of body’s normal functioning can lead to a number of health risk, sometimes, these are life threatening. The fluctuation of heart rate for longer time enhances the risk of low blood supply to the organs; it can also affect the breathing rate. It would result in tingling of extremities or trouble in concentrating.It can cause high blood pressure, blood clots as well as stroke^[20]. It needs immediate medical care. It may also effect brain functioning. The long-term effect of glucose level fluctuation can lead to diabetes. These symptoms are mainly seen in diabetic patient. Sometimes, eating substances that are more sugary can raise the blood glucose level, or irregular regulation of glucagon and insulin can also lead to long-term fluctuation of blood glucose level^[21].

Production of energy in Mitochondria

There are a number of diseases, which are caused by the imbalance of homeostasis. In the case of lung diseases, cleft palate, rhinitis, tonsillitis, Heimlich maneuver can be caused due to imbalance of homeostasis. Smoking hampers the ciliary activity and destroys cilia, thus preventing mucus accumulation^[22]. On the other hand, heart blockage, stroke, high blood pressure etc can cause due to imbalance of homeostasis of heart function. Additionally, diabetes is entirely due to the imbalance of secretion of glucagon and insulin, which are the major effectors of the homeostasis mechanism of blood glucose level^[23].

Reference List

Bayeva M, Novel Regulators Of Mitochondrial And Cellular Iron Homeostasis (2012)

Domec J and Johnson D, “Does Homeostasis Or Disturbance Of Homeostasis In Minimum Leaf Water Potential Explain The Isohydric Versus Anisohydric Behavior Of Vitis Vinifera L. Cultivars?” (2012) 32 Tree Physiology

Geissler C and Powers H, Human Nutrition (Churchill Livingstone/Elsevier 2012)

Hagman D and Kratz M, Macrophage Infiltration Of Human Adipose Tissue And Its Association With Systemic Inflammation, Obesity, And Metabolic Disease (2012)

Hill R, Wyse G and Anderson M, Animal Physiology (Sinauer Associates, Inc Publishers 2012)

Kenney W and others, Physiology Of Sport And Exercise (Human Kinetics 2012)

Kovacs W and Ojeda S, Textbook Of Endocrine Physiology (Oxford University Press 2012)

Kovacs W and Ojeda S, Textbook Of Endocrine Physiology (Oxford University Press 2012)

Marieb E, Essentials Of Human Anatomy & Physiology (Benjamin Cummings 2012)

Munis J, Just Enough Physiology (Oxford University Press 2012)

Powers S and Howley E, Exercise Physiology (McGraw-Hill 2012)

Pray L, Pillsbury L and Tomayko E, The Human Microbiome, Diet, And Health

Raith M and others, “Effects Of Recombinant Human Keratinocyte Growth Factor On Surfactant, Plasma, And Liver Phospholipid Homeostasis In Hyperoxic Neonatal Rats” (2012) 112 Journal of Applied Physiology

Sherwood L, Essentials Of Physiology (Brooks/Cole Cengage Learning 2012)

Shier D, Butler J and Lewis R, Hole’s Essentials Of Human Anatomy & Physiology (McGraw-Hill 2012)

Silbernagl S and others, Color Atlas Of Physiology (Springer 2012)

Simpson S and Raubenheimer D, The Nature Of Nutrition (Princeton University Press 2012)

Slominski A, Sensing The Environment (Springer 2012)

Spasojevic I and Spasojevic I, “Integrative Concept Of Homeostasis: Translating Physiology Into Medicine” [2012] Nature Precedings

Sprague I, Cells And Human Health (Springer 2012)

Thibodeau G, Patton K and Anthony C, Structure & Function Of The Body (Elsevier/Mosby 2012)

Tortora G and Derrickson B, Principles Of Anatomy & Physiology (Wiley 2012)

[1] Bayeva M, Novel Regulators Of Mitochondrial And Cellular Iron Homeostasis (2012)

[2] Domec J and Johnson D, “Does Homeostasis Or Disturbance Of Homeostasis In Minimum Leaf Water Potential Explain The Isohydric Versus Anisohydric Behavior Of Vitis Vinifera L. Cultivars?” (2012) 32 Tree Physiology

[3] Geissler C and Powers H, Human Nutrition (Churchill Livingstone/Elsevier 2012)

[4] Hagman D and Kratz M, Macrophage Infiltration Of Human Adipose Tissue And Its Association With Systemic Inflammation, Obesity, And Metabolic Disease (2012)

[5] Hill R, Wyse G and Anderson M, Animal Physiology (Sinauer Associates, Inc Publishers 2012)

[6] Kenney W and others, Physiology Of Sport And Exercise (Human Kinetics 2012)

[7] Kovacs W and Ojeda S, Textbook Of Endocrine Physiology (Oxford University Press 2012)

[8] Kovacs W and Ojeda S, Textbook Of Endocrine Physiology (Oxford University Press 2012)

[9] Marieb E, Essentials Of Human Anatomy & Physiology (Benjamin Cummings 2012)

[10] Munis J, Just Enough Physiology (Oxford University Press 2012)

[11] Powers S and Howley E, Exercise Physiology (McGraw-Hill 2012)

[12] Pray L, Pillsbury L and Tomayko E, The Human Microbiome, Diet, And Health

[13] Raith M and others, “Effects Of Recombinant Human Keratinocyte Growth Factor On Surfactant, Plasma, And Liver Phospholipid Homeostasis In Hyperoxic Neonatal Rats” (2012) 112 Journal of Applied Physiology

[14] Tortora G and Derrickson B, Introduction To The Human Body (John Wiley & Sons 2012)

[15] Sherwood L, Essentials Of Physiology (Brooks/Cole Cengage Learning 2012)

[16] Tortora G and Derrickson B, Principles Of Anatomy & Physiology (Wiley 2012)

[17] Shier D, Butler J and Lewis R, Hole’s Essentials Of Human Anatomy & Physiology (McGraw-Hill 2012)

[18] Thibodeau G, Patton K and Anthony C, Structure & Function Of The Body (Elsevier/Mosby 2012)

[19] Silbernagl S and others, Color Atlas Of Physiology (Springer 2012)

[20] Slominski A, Sensing The Environment (Springer 2012)

[21] Simpson S and Raubenheimer D, The Nature Of Nutrition (Princeton University Press 2012)

[22] Spasojevic I and Spasojevic I, “Integrative Concept Of Homeostasis: Translating Physiology Into Medicine” [2012] Nature Precedings

[23] Sprague I, Cells And Human Health (Springer 2012)