Independent Project: Biology Sketchbook
Skeletal System, Muscular System, Circulatory System
Development of the Embryo and Decomposition Stages are optional if I have already done 15 hours worth of work
I chose to focus on human anatomy, and more of the human development and the body decomposing stages. I find it intriguing and I have been studying that subject for a while. In my spare time, I study the physiology of the human body and human embryo
Below are images of the Skeletal System:
Skeletal System, Muscular System, Circulatory System
Development of the Embryo and Decomposition Stages are optional if I have already done 15 hours worth of work
I chose to focus on human anatomy, and more of the human development and the body decomposing stages. I find it intriguing and I have been studying that subject for a while. In my spare time, I study the physiology of the human body and human embryo
Below are images of the Skeletal System:
Images of the Circulatory System
Images of the Muscular System
Images of the Decomposition
I included a written piece on the stages of decomposition and what happens to the body during those stages.
Decomposition
Autolysis
Self Digestion/Self Destruction (cellular)
Autolysis is when the enzymes self destruct the cells/tissues caused by the depletion of oxygen within the body. It is usually known to start with the cells, which are still active. CO2 increases in the blood and the wastes gather and affect the cells. Organs, like the brain and the liver, that have high ATP (adenosine triphosphate) build up is more likely to be prone to autolysis. The cells break down and rupture by the cellular enzymes. Autolysis does not show visually until a few days later. After a few days, blisters filled with fluid appear on the skin. Fly colonization, Blowflies, flesh flies, and other insects come to infest a body for offspring development.
1-48 hours after death
Rigor Mortis 1-2 hours after death, muscles relax, 24-48 hours later muscles stiffen
The stiffening of the joints and muscles
The body becomes loose but eventually muscular tissues become rigid and not relaxed. This involved the muscles both voluntary muscles (muscles that can be moved by the person consciously) and involuntary muscles (muscles that work without our consciousness like the heart and stomach). After death, the body is limp and flexed. The jaw and eyelids, small muscles, and then the neck to bigger muscles. Temperature in the environment affects the rigidity, high temperature leads to rigidity happening much shorter than in cooler temperature. Cadaveric spasm is different than rigor mortis. Cadaveric spasm is early stiffening of the corpse before rigor mortis. This can can be seen as a freeze in time of their last action, like if the body was gripping onto a weapon or something and the body stays in that position. The self-destruction of the sarcoplasmic reticulum (a membrane-bound structure in muscle cells, like the endoplasmic reticulum in other cells) releases calcium ions and enables the attachment of actin and myosin (both are a type protein that form with each other) in muscle tissue. The ATP in the body works to separate the link between the actin and myosin. The ATP will eventually decrease, making the muscles stay firm.
Livor Mortis 2-4 hours after death
Accumulation/pooling of blood, Discoloration, 1-2 hours after death
When circulation of blood ceases, the blood, due to gravity, settles to the lower areas of the body that it can travel to. The blood in the lower areas become bright red to a dark blue/purple color. This is because of the color of deoxyhemoglobin. Blanching, is when the skin turns white when there is pressure pressing onto it, like when skin turns white when you press your finger onto your skin. The discoloration becomes fixed 12 hours later.
Algor Mortis
Cooling of the body
The body discontinues regulating internal temperature and it starts to cool down to becomes the same temperature as its environment. There are factors in which the cooling can be done faster or much slower, such as the size of the body. If the person is small, they will turn cooler much faster. A larger person will cool a bit slower. An obese body can keep their temperature longer than a skinny person who has thin limbs and less fat to keep them warm. The weather is another factor. The body can be exposed to a place with more heat or exposed to the sun and they would stay warm. There are many other factors as well as clothing.
Putrefaction 4-10 days after death
Degradation of tissue, decaying of the body
Microorganisms, like fungi and bacteria, degrade the tissue from the digestive tract in the body. Discoloration and bloating of certain body parts is what putrefaction shows in appearance. Gas, or fluids are products of decomposition by putrefaction. The gas products in the body appears with the swelling of the abdomen, face, and other parts. Bodies left in the open air, the process of putrefaction is faster, the bodies submerged in something or buried have the putrefaction process go slower.
Bloat
Swelling of the body and body parts due to the build up of gas (mainly)
Build up of gas (such as hydrogen sulphide, carbon dioxide, and methane) in the stomach, the cadaver becomes swollen due to the microorganisms in anaerobic putrefaction in the organs and tissues. The bloating usually begins in the abdomen then the other parts of the body. The pressure inside the body from gas build up forces the fluids, gas, and salts out of the openings of the body such as the nose, mouth, and anus. The bloating and the maggots feeding on the body makes the skin have ruptures.These ruptures let oxygen go back in the body and allows the fly larvae to develop. Maggots cramp in natural openings and gather together under the skin, causing the skin to slip and detach from the skin. The epidermis (outer skin) eventually begins to break down and shed because of these enzymes called hydrolytic enzymes which are between the outer and the second layer of skin. The slippage of the skin is common on the hands and feet and is often termed as “degloving”, the skin is like a glove that can be slipped off. This skin can be taken off for finding the identification of the body using the fingerprints. Intestinal anaerobic bacteria change hemoglobin (a red protein) into sulfhemoglobin (a green pigment formed by the reaction of hemoglobin with a sulfide in the presence of oxygen). The gases which accumulate in the body and the sulfhemoglobin transport throughout the body, giving the body a marbled appearance. Marbling of the skin is when the veins and arteries appear on the skin due to the development of sulfhemoglobin from bacteria reacting in the blood vessels. This begins the discoloration of the dermis from green and into the grey/black color, mostly where livor mortis formed.
Decay
Great loss of mass
This happens after the body deflates. The ruptured skin becomes black with microorganisms and scavengers in the skin. The stench of the body and a large number of Diptera larvae are present in this stage. Beetles (Coleoptera), have been present before and are now at the cadaver in a large group. Rove beetles are also evident as well as the Histeridae (Hister beetle). Liquefaction (process of making or becoming liquid), soft tissue begins with small bubbles appearing while the limit of the corpse can dry out. At this point, most of the beetles are done developing and leave the body to pupate in the soil. The Diptera larvae consumed the soft tissue from the body and left the skin and cartilage. The skin becomes dry and leathery if not covered. If covered, the flesh decays and shows the bones. If the corpse is lying flat on their back, the ribs and sternum will be supported by the dry skin and some tissue that is still connected. The purged fluids around the body and creates a cadaver decomposition island (CDI). Active decay ends when maggots migrate away from the body to pupate (stage of a larva to become a pupa).
The maggots are the larvae of a blowfly. Blow flies (Calliphoridae) are common around decaying meat and are attracted to the odor of rotting flesh. They like the decaying than the fresh meat. These flies lay their eggs in the open parts of the body such as wounds, mouth, eyes, etc. About 200 or so eggs are laid and cause damage to the cadaver that can lead to more putrefaction decay. Rats, cats, and dogs can also get the meat from the body as well as other larger animals. Fungi can be growing on the body and also in the intestines. The body appears to be caved in from the lack of flesh.
Tache Noir is an sign of death from the eyes. It is when a black discoloration on the eye appears. This happens when the eyes were not closed all the way and it was enough to be exposed to air. The eye becomes dry and a reddish-orange discoloration appears then into the black color.
Advanced Decay
Late Decaying stage
Insect activity is less active. In soil, the carcass (body) in the surrounding environment shows evidence of vegetation death. The CDI surrounding the carcass displays an increase in soil carbon and nutrients, and an increase in soil nitrogen. The bone becomes exposed and the body has degraded tissue around it with cartilage. The smell of decay is still there as well. This stage can be indicated by the migration of maggots, and other larvae. Beetles take the place of the maggots. The feeding of the beetles eat the dry flesh from the bones, making the bones left clean.
Dry Remains
The revival of plant growth around the CDI may happen and signals that additional nutrients is in the soil. The remains of the body are dry skin, cartilage, and bones, which become dry. The bones will become bleached if exposed to elements. It is referred to as completely skeletonized if all soft tissue is removed from the corpse. However, if portions of the bone are exposed, it is partially skeletonized.
Skeletonization
Tissue removal, being left with the skeleton
The bones will sometimes be seen with a few skin fragments, depending on the environment. The skin fragments can be preserved by clothing or in between the soil and the body. There are many factors in which the bones can have been messed with and missing. Animals can take the bones and disrupt the skeleton from identity. It is seen that if the environment has a higher temperature and the air is moist, the skeletonization process can be done much quicker. The skeleton will eventually start fossilizing when it is left alone for many years.
Here are the sources I referenced:
Goff, M. L. (2009). Early postmortem changes and stages of decomposition. In Current concepts in forensic entomology(pp. 1-24). Springer, Dordrecht.
Janaway, R. C., Percival, S. L., & Wilson, A. S. (2009). Decomposition of human remains. In Microbiology and aging(pp. 313-334). Humana Press.
Pinheiro, J. 0. (2006). Decay process of a cadaver. Forensic anthropology and medicine: Complementary sciences from recovery to cause of death, 85-116.
Vass, A. A. (2001). Beyond the grave-understanding human decomposition. Microbiology today, 28, 190-193.
Carter, D. O., Yellowlees, D., & Tibbett, M. (2007). Cadaver decomposition in terrestrial ecosystems. Naturwissenschaften, 94(1), 12-24.
Decomposition
Autolysis
Self Digestion/Self Destruction (cellular)
Autolysis is when the enzymes self destruct the cells/tissues caused by the depletion of oxygen within the body. It is usually known to start with the cells, which are still active. CO2 increases in the blood and the wastes gather and affect the cells. Organs, like the brain and the liver, that have high ATP (adenosine triphosphate) build up is more likely to be prone to autolysis. The cells break down and rupture by the cellular enzymes. Autolysis does not show visually until a few days later. After a few days, blisters filled with fluid appear on the skin. Fly colonization, Blowflies, flesh flies, and other insects come to infest a body for offspring development.
1-48 hours after death
Rigor Mortis 1-2 hours after death, muscles relax, 24-48 hours later muscles stiffen
The stiffening of the joints and muscles
The body becomes loose but eventually muscular tissues become rigid and not relaxed. This involved the muscles both voluntary muscles (muscles that can be moved by the person consciously) and involuntary muscles (muscles that work without our consciousness like the heart and stomach). After death, the body is limp and flexed. The jaw and eyelids, small muscles, and then the neck to bigger muscles. Temperature in the environment affects the rigidity, high temperature leads to rigidity happening much shorter than in cooler temperature. Cadaveric spasm is different than rigor mortis. Cadaveric spasm is early stiffening of the corpse before rigor mortis. This can can be seen as a freeze in time of their last action, like if the body was gripping onto a weapon or something and the body stays in that position. The self-destruction of the sarcoplasmic reticulum (a membrane-bound structure in muscle cells, like the endoplasmic reticulum in other cells) releases calcium ions and enables the attachment of actin and myosin (both are a type protein that form with each other) in muscle tissue. The ATP in the body works to separate the link between the actin and myosin. The ATP will eventually decrease, making the muscles stay firm.
Livor Mortis 2-4 hours after death
Accumulation/pooling of blood, Discoloration, 1-2 hours after death
When circulation of blood ceases, the blood, due to gravity, settles to the lower areas of the body that it can travel to. The blood in the lower areas become bright red to a dark blue/purple color. This is because of the color of deoxyhemoglobin. Blanching, is when the skin turns white when there is pressure pressing onto it, like when skin turns white when you press your finger onto your skin. The discoloration becomes fixed 12 hours later.
Algor Mortis
Cooling of the body
The body discontinues regulating internal temperature and it starts to cool down to becomes the same temperature as its environment. There are factors in which the cooling can be done faster or much slower, such as the size of the body. If the person is small, they will turn cooler much faster. A larger person will cool a bit slower. An obese body can keep their temperature longer than a skinny person who has thin limbs and less fat to keep them warm. The weather is another factor. The body can be exposed to a place with more heat or exposed to the sun and they would stay warm. There are many other factors as well as clothing.
Putrefaction 4-10 days after death
Degradation of tissue, decaying of the body
Microorganisms, like fungi and bacteria, degrade the tissue from the digestive tract in the body. Discoloration and bloating of certain body parts is what putrefaction shows in appearance. Gas, or fluids are products of decomposition by putrefaction. The gas products in the body appears with the swelling of the abdomen, face, and other parts. Bodies left in the open air, the process of putrefaction is faster, the bodies submerged in something or buried have the putrefaction process go slower.
Bloat
Swelling of the body and body parts due to the build up of gas (mainly)
Build up of gas (such as hydrogen sulphide, carbon dioxide, and methane) in the stomach, the cadaver becomes swollen due to the microorganisms in anaerobic putrefaction in the organs and tissues. The bloating usually begins in the abdomen then the other parts of the body. The pressure inside the body from gas build up forces the fluids, gas, and salts out of the openings of the body such as the nose, mouth, and anus. The bloating and the maggots feeding on the body makes the skin have ruptures.These ruptures let oxygen go back in the body and allows the fly larvae to develop. Maggots cramp in natural openings and gather together under the skin, causing the skin to slip and detach from the skin. The epidermis (outer skin) eventually begins to break down and shed because of these enzymes called hydrolytic enzymes which are between the outer and the second layer of skin. The slippage of the skin is common on the hands and feet and is often termed as “degloving”, the skin is like a glove that can be slipped off. This skin can be taken off for finding the identification of the body using the fingerprints. Intestinal anaerobic bacteria change hemoglobin (a red protein) into sulfhemoglobin (a green pigment formed by the reaction of hemoglobin with a sulfide in the presence of oxygen). The gases which accumulate in the body and the sulfhemoglobin transport throughout the body, giving the body a marbled appearance. Marbling of the skin is when the veins and arteries appear on the skin due to the development of sulfhemoglobin from bacteria reacting in the blood vessels. This begins the discoloration of the dermis from green and into the grey/black color, mostly where livor mortis formed.
Decay
Great loss of mass
This happens after the body deflates. The ruptured skin becomes black with microorganisms and scavengers in the skin. The stench of the body and a large number of Diptera larvae are present in this stage. Beetles (Coleoptera), have been present before and are now at the cadaver in a large group. Rove beetles are also evident as well as the Histeridae (Hister beetle). Liquefaction (process of making or becoming liquid), soft tissue begins with small bubbles appearing while the limit of the corpse can dry out. At this point, most of the beetles are done developing and leave the body to pupate in the soil. The Diptera larvae consumed the soft tissue from the body and left the skin and cartilage. The skin becomes dry and leathery if not covered. If covered, the flesh decays and shows the bones. If the corpse is lying flat on their back, the ribs and sternum will be supported by the dry skin and some tissue that is still connected. The purged fluids around the body and creates a cadaver decomposition island (CDI). Active decay ends when maggots migrate away from the body to pupate (stage of a larva to become a pupa).
The maggots are the larvae of a blowfly. Blow flies (Calliphoridae) are common around decaying meat and are attracted to the odor of rotting flesh. They like the decaying than the fresh meat. These flies lay their eggs in the open parts of the body such as wounds, mouth, eyes, etc. About 200 or so eggs are laid and cause damage to the cadaver that can lead to more putrefaction decay. Rats, cats, and dogs can also get the meat from the body as well as other larger animals. Fungi can be growing on the body and also in the intestines. The body appears to be caved in from the lack of flesh.
Tache Noir is an sign of death from the eyes. It is when a black discoloration on the eye appears. This happens when the eyes were not closed all the way and it was enough to be exposed to air. The eye becomes dry and a reddish-orange discoloration appears then into the black color.
Advanced Decay
Late Decaying stage
Insect activity is less active. In soil, the carcass (body) in the surrounding environment shows evidence of vegetation death. The CDI surrounding the carcass displays an increase in soil carbon and nutrients, and an increase in soil nitrogen. The bone becomes exposed and the body has degraded tissue around it with cartilage. The smell of decay is still there as well. This stage can be indicated by the migration of maggots, and other larvae. Beetles take the place of the maggots. The feeding of the beetles eat the dry flesh from the bones, making the bones left clean.
Dry Remains
The revival of plant growth around the CDI may happen and signals that additional nutrients is in the soil. The remains of the body are dry skin, cartilage, and bones, which become dry. The bones will become bleached if exposed to elements. It is referred to as completely skeletonized if all soft tissue is removed from the corpse. However, if portions of the bone are exposed, it is partially skeletonized.
Skeletonization
Tissue removal, being left with the skeleton
The bones will sometimes be seen with a few skin fragments, depending on the environment. The skin fragments can be preserved by clothing or in between the soil and the body. There are many factors in which the bones can have been messed with and missing. Animals can take the bones and disrupt the skeleton from identity. It is seen that if the environment has a higher temperature and the air is moist, the skeletonization process can be done much quicker. The skeleton will eventually start fossilizing when it is left alone for many years.
Here are the sources I referenced:
Goff, M. L. (2009). Early postmortem changes and stages of decomposition. In Current concepts in forensic entomology(pp. 1-24). Springer, Dordrecht.
Janaway, R. C., Percival, S. L., & Wilson, A. S. (2009). Decomposition of human remains. In Microbiology and aging(pp. 313-334). Humana Press.
Pinheiro, J. 0. (2006). Decay process of a cadaver. Forensic anthropology and medicine: Complementary sciences from recovery to cause of death, 85-116.
Vass, A. A. (2001). Beyond the grave-understanding human decomposition. Microbiology today, 28, 190-193.
Carter, D. O., Yellowlees, D., & Tibbett, M. (2007). Cadaver decomposition in terrestrial ecosystems. Naturwissenschaften, 94(1), 12-24.