Your skull is made up of 22 bones. 2/3 of it consists of cranial bones, even though there are only 8 of them. The other 1/3 is your face.
Two main goals of the cranial bones: protects your brain, acts as an anchor for neck and face muscles.
The 8 bones are connected together by sutures (because they look like they've been sewn together) - and it is a tight fuse that doesn't allow anything through.
The frontal bone - at your forehead, it's on the FRONT. When babies are born, this bone is actually in 2 pieces to allow baby's head to smush during delivery. It fuses together so tightly, that it becomes one bone by eight years old.
Fontanels = soft spots that babies have that allows for rapid brain and head growth. Babies have 6 total soft spots. All of them close up by 3 months old except the big one in the front.
Steve's story: His daughter's soft spot would sink in and she would cry. His mother-in-law would fill her mouth with water and then suck the baby's soft spot out. *DO NOT TRY THIS AT HOME!!*
Sunken in soft spots can be a sign of dehydration because there is lots of blood vessels in that area.
The bones in your face and head have cavities and tunnels (called sinuses) that allow nerves and blood vessels to travel through, as well as keep air pressure stable.
Question 1: Skull fracture? Can possibly happen on a suture where two bones separate, but more often an actual crack in one bone.
Question 2: Is brain bleeding always dangerous? Always potentially fatal? Yes, because your brain is closed in. Brain bleeds are classified into levels, and part of it has to do with how deep in the brain it happens, and how much pressure it puts on the things around it. Blood vessels are found all throughout your brain, and the blood that flows through them has its designated space. If the blood comes out of the blood vessels, then it starts crowding out the things around it (which can be important parts of your brain). Sometimes people may have a brain bleed and they will remove part of the skull bone to relieve the pressure.
Story #2: Orbital hemorrhage caused vision loss and feeling loss in lower extremities. If the nerve signal is interrupted temporarily, then the functions of those parts will return. If the nerves are damaged permanently, then those functions will be lost permanently. This was caused by blunt force trauma. As long as the rest of you is healthy, and the injury is fully healed, I would not expect it to happen again out of the blue.
Where does the bottom of your brain sit? Your cranium has a floor. One of the bones that make up the floor is called the Sphenoid bone (my favorite bone).
You can reach it and wiggle it and help with sinus pressure and drainage (it's a neat trick!) It works by creating tiny pressure differences in your sinuses.
The outside of your skull bones are rather smooth. The inside of those bones are bumpy and jagged because it gives places for the membranes to anchor and keep the brain buoyant and centered.
Review: Epidermis = top layer of skin. Living cells divide and then add in proteins that causes cells to harden as they die and become and protective layer to keep out water and dirt and critters. Some of those proteins give your skin its color (melanin) and they help block and reflect UV light from the sun to keep the living cells from being damaged.
Mutations = if UV light damages the cells' DNA, then when the cells divide and replicate, they copy the "error" and reproduce an abnormal cell. If certain mutations cause the cells to die, others cause the cells to be weak, but others cause the cells to become cancer.
3 types of skin cancer
- Basal cell carcinoma - most common of these 3, more common in people with fair skin. Skin growth is flesh colored, can look like skin tags. Caused when a basal cell gets mutated and starts to grow.
- Squamous cell carcinoma - more common in people with fair skin. Scaly patches or sores that open, start to heal but reopen and never heal. Caused when a keratinocyte (living, dividing skin cell) gets mutated in the middle of replicating.
- Melanoma - Moles are just a place where a lot of melanocytes gather in one place, but sudden moles or dark spots can be the tip of a bad iceberg. This is the deadliest type of skin cancer. Caused by mutations in the melanocytes.
Some benign (harmless) skin characteristics can resemble skin cancer, thus it's easy to overlook them in the early stages.
Tool for early detection of melanoma
A - Asymmetry - you can't fold it in half and all the edges match
B - Board - jaggedy, sharp boarders
C - Color - uneven color
D - Diameter - > 6mm (bigger than the eraser of a #2 pencil)
E - Evolving - changes shape, size, or color in a short amount of time (< 1 month)
This is why the National Skin Cancer Foundation recommends you do a monthly skin scan to check skin characteristics for changes or new ones.
Early detection is the number one step to improve survival of all cancers.
Precancer = Actinic Keratosis - dry and flakey places in the skin, can be the precursor of Squamous Cell Carcinoma. Usually shows up after 40 years old.
Cancer is not just a disease that happens to the aged, but as you age, the probability of you being exposed to something that could mutate your cells goes up.
Most common skin issues:
1. Dry skin - usually due to your skin not having enough of its own natural oils (probably strips from soaps, cleansers, chemicals). Moisturizing lotions and creams are "greasy" to try and match the oil of your skin. The oil make the skin waterproof - keeps water out, but also keeps water in (prevents evaporation)
* Eczema - dry skin with an immune/inflammation component. The deeper layers of the skin will release inflammation chemicals that irritate the other cells in the area and lead to redness, pain, and swelling. It's common for kids to have eczema but then grow out of it, but other conditions can cause eczema to flair (in my case, pregnancy)
2. Rash - one of the most ambiguous symptoms to try and figure out what the root cause is. Rashes can be round or splotchy, symmetrical or asymmetrical, raised or flat, big or small. Rashes are caused by some type of inflammation process (most commonly histamines). Rashes are a sign that your body has been offended by something - either from the inside and then the chemicals reach the skin to cause rash, or from the outside that touched your skin and caused chemicals to be released.
*Hives - a very distinctive rash with raised, irregular borders that may be red, but can also maintain their "flesh color". Most commonly involve histamines, thus antihistamines (like benadryl can help them go away). Can possibly be triggered by stress (the stress hormones cause a chain reaction of chemical release which may lead to hives).
Viral exanthem - "exit rash"; a rash that kids will get when their body has finally beat a virus. Some start at the top of the body and then moves down to their feet. Others start on the torso or core and then move out to the extremities. Antihistamines do not help it, but they rarely hurt or itch or bother the kid in any way.
Blackheads - there are different pores in your skin (sweat glands, oil glands, hair follicles). The oil on your face helps to trap bacteria and dirt that could get deeper in your skin and possibly hurt you. The goal of cleaning your face, is to cleanse off the "dirty" oil, but not all the oil (because the result is either dry skin or over-production). So the dirty oil plus the shedding dead skin cells can clog up any of these pores. Blackheads are specifically when hair follicles are clogged - and they look black b/c the melanin proteins that get built into hair can be seen. Generally small blackheads and whiteheads are not painful, unless a lot of bacteria are involved and they begin to fester.
*Cystic acne is when a larger area that involves multiple pore or hair follicles get clogged and infected with bacteria and then the spot can become swollen and painful (and unsightly).
Hormones regulate the oil production, that's why puberty increases acne, stress increases acne, all of the transitions surrounding pregnancy can increase acne. As long as you have hormones, you're going to have a risk of acne.
Also, working in really dirty environments can increase the amount of dirt that could clog up pores.
Ringworm = tinea corporis (there's no worm involved, it's a fungus). Classic circular rash that is red and flakey and possibly flesh-colored in the middle.
If it's on your head (tinea capitis = cradle cap). If it's in your groin (tinea cruris = jock itch). If it's on your feet (tinea pedis = athlete's foot).
Tinea vesicolor = the fungus causes the skin to lose pigment (this is NOT vitiligo, which is the death of melanocytes and they don't grow back, Michael Jackson).
Candida is the yeast that is a part of your natural skin flora, but can lead to rash if it gets out of balance.
If there is anything on your skin that bothers you, see your doctor!
Two products to protect your skin from sun exposure:
- Sunscreen - filters the sunlight *like a screen on a window*; made up of organic compounds (like chemistry, not vegetables) that absorb UVA and/or UVB rays that reach your skin. These are the products labeled with SPF numbers.
- Sunblock - used to be opaque because it is supposed to completely block any sunlight from getting to your skin. *Think Screech from Saved By The Bell*. Full of reflective particles to bounce the sunlight away from your body. The particles have been micronized by technology so it is transparent to your eyes, but not to the UV light from the sun.
Lesson on Light: The light comes from the sun. There's visible light (ROYGBV) and that light bounces off of things and as it goes in your eyes, that's how you can see things. Along with the light we see, there is ultraviolet light (waves of light that are shorter and more energetic that the violet color light). There are 3 types of UV light - 1 is absorbed and reflected by the atmosphere so it never makes it to us. Then there is UVA and UVB. UVA is more energetic and is most responsible for causing cell mutations that lead to cancer. UVB is less energetic and is most responsible for causing your skin to tan.
UV rays travel through these layers of the skin and stimulate the living and dividing cells to divide more and create more melanin. Reminder: melanin is your skin's natural skin protectant because it will absorb UV rays in the higher layers to help prevent it from reaching the dividing cells.
SPF math (Sun Protection Factor)
Step 1: find out how long you can be out in the sun without protection before your skin starts turning red or burning (example: 15 minutes)
Step 2: Multiply that "unprotected time" by the SPF number on the bottle (SPF 15) to get your "protected time" (15 x 15 = 225 minutes = 3 hr 45 min**)
**This is only if you don't sweat and don't get wet. But it's very hard to be in the sun and NOT sweat. Plus your natural skin oils dilute it the longer it stays on the skin.
The Skin Cancer Foundation recommends reapplying sunscreen every 2 hours no matter what. They also recommend that you use SPF 15 (or higher) sunscreen, that blocks UVA and UVB, every day, especially on your face, all year round. The daily UV exposure, if you're unprotected, is what they suspect leads to a greater chance of skin cancer.
They also recommend UV-blocking sunglasses.
Clothes and hats are the best way to protect your skin from sun exposure.
Stay inside during peak hours (10 am - 4 pm) of radiation (less atmosphere to block and deflect sunlight).
Do a monthly, head-to-toe, skin scan to check for new or changing moles, freckles, and skin tags (or get a friend to help). EARLY DETECTION!!
Have your doctor check your skin once a year.
Vitamin D is made by your skin.
Lots of foods are fortified with Vitamin D.
Vitamin D2 is plant-based. Plants make vitamin D then you eat them and absorb it. This is also the type of Vitamin D that is added to other foods.
Vitamin D3 is animal-based. You absorb very little Vitamin D from animal food sources. This is the type that your skin makes.
The membranes of your cells are made up of cholesterol. It allows them to stay fluid and flexible, and it allows diffusion of some nutrients.
UV-B rays come down from the sun and travel through the top layer of your skin. Those rays interact with the cholesterol in the skin cells and cause it to break away and it starts a changing process as that loose molecule makes it way to the bloodstream. *Think the Hulk transformation*. By the time it reaches the bloodstream, it has become D3 (~ 12 hour long process).
Vitamin D3 = Calcitriol (tri = 3)
Vitamin D2 = Calcidiol (di = 2)
The news will tell you that Vitamin D is needed to prevent the Winter Blues or that it's good for your bones.
Vitamin D has 2 jobs to help with your bone health. Vitamin D tells your intestines to make calcium-carrying and phosphorus-carrying proteins, so when you eat foods that contain calcium or phosphorus, the cells of the small intestines will have the ability to transport these molecules into the bloodstream. Then in your periosteum (the membrane that covers your bones), Vitamin D works with parathyroid hormone to tell the periosteum cells to make the same kinds of proteins to get the calcium out of the blood and into the bone-building process.
Vitamin D also has an important role in your immune system. It plays a part in cell differentiation. Vitamin D helps an immune system cell know which type of cell it needs to specialize as (B-cell, T-cell, macrophage) to do the optimum job based on the type of invader that has entered your body.
While sun exposure stimulates Vitamin D production, there has to be a balance to avoid skin aging and risks of cancer. Taking Vitamin D supplements can be a safer alternative.