Looking at bones and muscles as well as a bit about blood cells while using a cows leg

Looking at bones and muscles as well as a bit about blood cells

My class has just recently started the Medical Science part of the Scipad and with this is multiple experiments/investigations on dead animals or other things. The first one we had the luxury of doing was a cow leg. With this cow leg, our aim was to witness how muscles push. The thing with muscles is they will only ever push never pull which is why you have multiple muscles of the opposite sides in your body. Such as your arm and legs. For example when you put your arm in an L shape your tricep relaxes but your bicep contracts to push it out, the opposite happens when you bring your arm back down.

A bit about muscles

In the cow leg, you can see a bunch of flesh around the knee and the rest stripped this is because this was sent to butcher first, however, the main stuff we are looking at is there since people don't generally eat them. We used the top bone to control the muscles so for example when we pulled down the bone the bottom muscle near the knee would contract while the top one relaxes, you can see this in the small movement of the knee. There is also a white circle on it that would come in and go out depending on the movement of the leg, this is the knee cap. You can see this on the top right of the fleshy bit of the knee. On the opposite side of the knee cap, you can also find a small socket bit where some of the bone would come into when pulling the leg down.

Muscle Cramp

A muscle cramp is a common thing that affects people. It is caused by many different things. For example, overuse of the muscle, pregnancy because of losing of minerals in the body, exposure to cold temperature, diseases that affect muscles, positioning your legs in awkward ways, sitting for too long, standing still for too long, dehydration and certain medicines/drugs. As you can see muscle cramps can generally happen with underuse/overuse as well as a lack of water and minerals. When the muscle doesn't have what it depends on or not used in the right amount it will cramp.


A muscle cramp is when the muscle painfully contracts by itself, this causes pain in the body at the location and generally lasts several seconds to a few minutes. It only happens to muscles we can control so mostly legs and arms. Scientists have labelled cramps into different forms such as the true cramp. A true cramp is when a muscle of generally a group of muscles is triggered to cramp by the nerve system. These are the most common cramp triggered by stuff like massive injury, rest and dehydration and body fluid changes as well as low mineral count in your body. Tenaty is another type of cramp where all nerve systems are activated. This type of cramp will generally cause your muscles around the mouth to tingle and go numb, it can cause spasm in your hands and wrists. This is triggered by low blood calcium, low magnesium, muscle stimulation and hyperactivity. They sometimes can be extremely similar to true cramps because they have some of the same causes.

How do bones/joints work

How do bones work? Well, basically bones can't move so it needs some type of thing to give the force required to move it. If we didn't have muscles we would be lifeless, muscles open our mouths, our body depends on these muscles to survive. Muscles are connected to the bones through what's called a tendon. A tendon is a flexible stretchy piece of flesh in your body, it is needed to be this way since if it wasn't the tendon would just break when the muscle contracted. The tendon is required so that most muscles are kept in place and in some cases around your body they connect special muscles such as your eye to the rest of your body allowing you to use this body part. Now going back to just bones, to form stuff like your leg and arm two bones will connect and create a joint. Without joints, our skeletons would fall apart and without multiple bones, for stuff like the leg, we wouldn't have the flexibility we have.


If we had one bone in our leg we would not be able to move half of it while keeping the other halve the same. We can do this with our legs and arms because of our elbows/knees which are joints. Bones can't really move against each other as well which would cause them to break and wear away so the joints also provide a solution to that! First of all, ligaments connect the two bones, to stop the bones wearing away the ends of the bones have cartilage which reduces friction between the bones and acts as a shock absorbent. It is kept slippery and lubricated so it doesn't wear away as well by the synovial fluid which is produced by a synovial membrane. This is the structure of a joint and allows the movement and flexibility we have.

Osteoporosis

Ever wondered why old people have so brittle bones and commonly can break a bone just by falling? This is because the cartilage wears away possibly because of a lack of fluid or other reasons, because of this the bone then wear away with no cartilage to s/top them and eventually the bones get extremely weak causing this to happen. This problem can also occur in younger people because of the same reasons old people just have it more commonly because of living so long. Below is a video of us cutting through the bone.

Bone Growth

When you are born you have tiny bones, you don't have the type of bones you would have as an adult. Overtime bones will fuse together as well as growing. As you age cartilage grows bigger and that cartilage then forms into a bone with calcium, later on, this process is called ossification. During this process, hundreds of calcium layers and phosphate salts gather on the cartilage. After a while, this will cause the cartilage cells to die. Once this is done blood cells will grow into tiny pockets in this area, these blood cells will help by containing a unique cell called osteoblasts. Osteoblasts help carry additional calcium and produce a substance called collagen fibres. This fibre provides strength and cushioning, it is found all around our body with a lot in the skin and around tendons/joints.



These osteoblasts also produce cortical bones that will surround the cartilage. This bone is found throughout the body around organs it supports the whole body and is responsible for storing and releasing certain chemical elements. After a while, a cell called osteoclasts will end up in a developing bone. This cell will use an acid called Hydrolytic enzymes and other acids to dissolve a small bone part to make room for more bone marrow. This is repeated until most of the cartilage in your body has dissolved and all your bones have grown which generally happens around the age of 20. A topic relating to this is what happens when your bone breaks?


Well, how does a bone break anyway? A bone generally breaks when to much force is applied to it such as a heavy object falling onto your arm. This applies a lot of pressure onto your arm and if it is heavy enough and fell far enough your bone will most likely break. When a bone breaks it will attempt to heal itself for this to happen it must be positioned in a certain way, this is why you are given casts. The body will create blood clots around the broken bone and shortly after the bone will start to create small threads. These threads will eventually combine through the same method that a bone grows.

A bit about blood cells and bone marrow

Inside the bone you can find the bone marrow, there are two types of bone marrow. There are however two types of bone marrow and two stem cells. The Hemopoietic stem cell produces blood cells whereas the Stromal stem cell produces fat cartilage and bone. The two types of bone marrow are yellow while the other is red.


You start your life with only red bone marrow however you will gain yellow bone marrow based on fat. Although as you get older you WILL start to gain more yellow bone marrow. Red marrow focuses completely on blood cell production so in the case of massive blood lose the body will convert yellow marrow into red marrow to aid in stopping death. The red bone marrow will produce white blood cells, red blood cells and platelets. White blood cells are responsible for defending you from infection in your blood, they are produced in a higher concentration when someone is fighting off a disease/infection and are there killed off after defeating an infection. However white blood cells are at an extremely low quantity in our blood only being 1% of the cells located in our blood, however, of course, this % will slightly increase when an infection is located in you.


Platelets are tiny fragments in your blood that will create clots to help with bleeding however if they somehow clot in your blood and that clot travels to your heart you will have a heart attack, and if it goes to your brain you will have a stroke. These are both extremely dangerous conditions that can easily kill you. Platelets are less than 1% of the produced blood cells. Red blood cells contain chemicals that transport oxygen through your blood they make up 45% of the cells in your blood and are required so much because our blood needs to transport oxygen to give to our muscles and organs. Without this oxygen collected from the lung and then transported with the help of these red blood cells, we would end up dead as our muscles and organs require oxygen like our lungs do and there is no way to bring it around without the blood cells. Plasma is also part of the blood cell group it carries nutrients through the blood so it contributes majorly to the digestive system however bone marrow does not produce this.