Osteoporosis - A Silent Disease

Bone to the left is normal bone, bone to the right is osteoporotic bone.





Osteoporosis is a disease that results in reduction in bone mass, the bones become thinner, lighter, more porous and more brittle.

It is a disease which is common among old people. In everyone, progressive loss of bone density starts after mid-30s.



















Women during menopause/postmenopausal (due to hormonal change, in particular a drop in oestrogen level) tend to loose their bone density faster than men. After reaching 65-70 years of age, this rapid rate of bone density loss decreases, reaching the same level as men.

Osteoporosis affect the whole body, but the most affected areas are the part which support most of the body's weight: the vertebrae, pelvic-leg system (hip, femur).

Risks:

1. fracture of the vertebrae & bones (hip, wrist, etc)

2. reduction in height over time

3. stooped posture.







Prevention:




1. taking diet rich in calcium, phosphate, vitamin D.

2. carry out physical exercise (weight-bearing exercise) that stress the bone

3. stop smoking

4. stop alcohol abuse

5. maintain healthy body weight

Remember: Osteoporosis has NO symptoms until a bone is fractured!

Joint replacement surgery

Here are some useful videos to help you understand some common joint surgery related to arthritis (joint inflammation) at the hip, knee & shoulder.

click here to watch the videos...

Dengue fever & Dengue haemorrhagic fever

1. Dengue is transmitted by the bite of an Aedes mosquito (main vector) infected with any one of the four dengue viruses (DENV 1, 2, 3, 4).
   
2. Dengue affects infants, young children and adults.
   
3. Symptoms appear 4-7 days after the infective bite. In some cases, it can be without symptoms or with mild influenza symptom.
   
4. What are the symptoms for Dengue Fever (DF)?
   * high fever (with severe headache)
   * pain behind the eyes
   * muscle and joint pain
   * with or without rash
   
5. What are the symptoms for Dengue haemorrhagic fever (DHF) - can be fatal.
   * fever,
   * abdominal pain
   * vomiting
   * bleeding from mucosa (from gums, nose)
   

Treatment:

1. There is NO vaccine & antiviral drugs for Dengue.
   
2. NO Aspirin or Brufen because they can cause gastritis and/or bleeding.
   
3. Antibiotic does not help either.
   
4. Paracetamol (eg: Panadol) are given for fever above 39 C.
   
5. Oral rehydration solution/fluid/juices/electrolytes are given to patient with moderate dehydration (caused by vomitting & high body temperature)
   
6. Plenty of bed rest
   

Life Cycle of Aedes mosquitoes:

Aedes mosquitoe needs just ONE (1) week to develop from Egg through larva & pupa, then into Adult. Therefore, you have only ONE (1) week to break their life cycle. How?

What can WE do?

1. About 80% of the reported dengue cases occured at home or at places with high Aedes Breeding Index.
   
2. Therefore WE must play our part in preventing the spread of dengue.
   
3. Spend 10 minutes weekly to 'search & destroy' aedes breeding sites inside and around your house.

• Inside the house:
  * flower pots
  * water containers
  * Refrigerator under tray
  * water tank
  
• Outside the house:
  * Unused tyres
  * coconut shells, bamboo, plastic bags
  * broken bottles/glass that could hold water
  * drainage pipes
  * banana, bamboo and yam stumps.
  
  
  
• Prevention and Control:
  * change water in vases, flower pot bases & water tanks. Clean thoroughly once a week.
  * cover all water containers to prevent mosquitoes from breeding.
  * place all containers that can collect water, such as cans & bottles into plastic bagas and dispose of at designated places.
  * ensure gutters (of house roof) are not blocked.
  * add adequate amount of larvicide into water storage to kill larvae every 3 months.

Related links:

1. Dengue claims lives of two sisters in Pulau Pinang - NST
   
2. Dengue claims lives of two sisters in Penang - video
   
3. Dengue around Subang Jaya - SJ Echo
   
4. Video tempat pembiakan Nyamuk Aedes - MOH
   
5. Chikungunya infection - An emerging disease in Malaysia
   *Chikungunya virus is also transmitted by Aedes mosquito
   
6. Reference: WHO Dengue

Osmosis - Plasmolysis & Deplasmolysis in plant cells

1) Plasmolysis?

When plant cells are immersed in hypertonic solution, water molecules diffuse out of the plant cells (the vacuoles) by osmosis. The cells shrinks (plasmolysis) because vacuole & cytoplasm lose water, and plasma membrane pulls away from the cell wall. The plant cells become flaccid, the plant wilts and this could lead to death.
Eg: when plant is not receiving water supply for long period of time, or excessive fertilisers are given to the plant, etc.

In the video below, you will get the same result when the salt solution is replaced by excessive use of fertilisers (at high concentration).



2) Deplasmolysis?

When a plasmolysed plant cell is immersed in hypotonic solution (eg: distilled water), the plant cell becomes turgid again due to uptake of water molecules into plant cell by osmosis.

How birds fly & fish swims

These are good videos to share with you.

1) how birds fly.



2) watch this...... how the 'Golden Plover' can do a 88 hours non-stop flight from Alaska to Hawaii, which is 2,500 miles apart. Amazing!






3) how fish swims

What muscles are used during walking?

What muscles are used when we walk?

We learned this in chapter 2 (F5). Muscles involved are the calf muscles, Hamstrings/biceps femoris, Quadriceps/Quadriceps femoris. Refer yr notes.

Actually, more muscles are involved during walking. Watch this video.

Form 4 Chapter 3 - Movement of sub across the PM (Part 2)

In this part . . .

we shall look at the type of transport involves in transporting substances in & out of the cell.

1) There are 2 types of transport: Passive transport (PT) and Active transport (AT)

• PT:
  i) No energy (ATP) is used by cell during movement of substances.
  ii) substances move according to their concentration gradient.
  * concentration gradient is the difference in the concentration of a substance between 2 regions.
• AT:
  i) needs energy (ATP)
  ii) substances (ions/molecules) move against concentration gradient across the PM.

2) There are 3 different types of PT: Simple diffusion, Osmosis, Facilitated diffusion.

• Simple diffusion:
  
  
  i) a physical process
  ii) definition: is the net movement of molecules/ions from a region of higher concentration to a region of lower concentration, according to a concentration gradient, until an equilibrium is achieved. (dynamic equilibrium)
  iii) Eg: the exchange of gases between the alveoli & the blood cap. at the lungs.
  
• Osmosis:
  i) involves only water molecules.
  ii) definition: is the net movement of water molecules from a region of low solute concentration to a region of high solute concentration through a semi-permeable membrane.
  iii) you can study osmosis using a simple osmometer at the lab.
  iv) Eg: the uptake of water by the plant roots.
  
  
  
• Facilitate diffusion:
  i) definition: movement of hydrophilic molecules/ions (eg: glucose, ions) across the PM with the help of transport protein.
  ii) Carrier protein: are specific, has binding sites for molecules to bind on.
  iii) Pore protein: are transporters which are always open, usually hv charges & specific shape, to transport small, dissolved particles (ions)
  iv) Eg: Absorption of certain digested foods/nutrients in the villi of the small intestine. eg; glucose.
  
  
  *transport proteins such as uniport, symport, antiport are not in spm syllabus.

3) The Active Transport:

• i) definition: is the movement of molecules or ions across the PM against their concentration gradients, that is from a region of lower concentration to a region of higher concentration, which requires carrier proteins & cellular energy (ATP).
• ii) Carrier proteins, often called pump, has active sites. One site binds with a particular molecule/ion. The other site binds with ATP (phosphate molecule).
• iii) Eg: sodium-potassium pumps in animal cells (nerve & muscle cells)
  * 3 sodium ions are released to the outside of the cell while 2 potassium ions are brought into the cell.
• iv) other eg: the uptake of mineral ions by the plant roots.
  
  

Form 5 Chapter 2 - Locomotion & Support (Part 1)

Here are the summary . .

1) Skeleton is the supporting structure which:

• enable movement when the bones interact with the skeletal muscles
• give shape & give mechanical support for the body
• protect the internal organs. (eg: the skull protects the brain, the ribcage protects the lungs & heart)
• provide firm base for attachment of skeletal muscles.
• produces blood cells - eg Red Blood Cells are formed in the bone marrow of the long bones.
• stores minerals, eg: calcium & phosphate.

2) 3 types of skeletons:

• Hydrostatic skeleton - consists of internal fluid within a confined spaces of the body & is kept under pressure surrounded by muscles. eg: earthworm.


• Exoskeleton - non-living structure (eg: cuticle) that covers the surface of the body. It support the internal organs, protect internal structure from damages. eg: grasshopper.


• Endoskeleton - consists of a rigid framework of bones & cartilage which muscles are attached. It maintains body shape, support soft body tissues, protecting internal organ from injury.
  

3) The Human Skeletal System.

a) Is divided into 2:

• i) Axial skeleton: the skull, the vertebral column, ribs & sternum (ribcage)
• ii) Appendicular skeleton: pectoral girdle, pelvic girdle, bones of the limb

b) A typical vertebra consists of:

• 1) Centrum (solid body)
• 2) Neural canal
• 3) several neural processes

• Function of the structure of a vertebra:
  1) Neural spine - provide surface for attachment of muscles & ligaments.
  2) Transverse process - same as above
  3) Neural arch - protects the spinal cord.
  4) Centrum - provides support, absorb shocks, resists compression.
  5) Neural canal - provides the passage for spinal cord.
  
  
  6) articular processes/facets - provides surfaces which articulates with the next vertebra/bones.

4) Axial skeleton:

• consists of the skull, the vertebral column, ribs, sternum.


• i) Skull
  a) consists of cranial bones (cranium) & facial bones.
  b) functions:
  1) the cranium enclose & protect the brain.
  2) the facial bones protect & support the entrance of digestive & respiratory system.
  
  
• ii) The vertebral column:
  
  
  
  a) consists of 33 small vertebrae.
  b) divided into 5 parts :
  1) Cervical vertebrae (neck, 7 vertebrae, C1-C7, C1 is known as atlas, C2 is known as axis)
  2) Thoracic vertebrae (thorax & chest region, 12 vertebrae, T1-T12)
  3) Lumbar vertebrae (lower back region, 5 vertebrae, L1-L5)
  4) Sacrum (lower back region, 5 sacral vertebrae, fused, S1-S5)
  5) Coccyx (tailbone, 4 fused caudal vertebrae)
  c) Intervertebral disc is located in between the vertebrae.
  
  
  1) made up of cartilage.
  2) functions: act as cushion to absorb shocks when moving, to reduce friction btw
  vertebrae.
  d) Function of vertebral column:
  1) support the head/skull & body
  2) encloses & protect the spinal cord
  3) provide base for attachment of muscles to the back
  4) ...
Question: why the vertebral column is made up of 33 vertebrae, not one long bone?
e)Main characteristic of vertebrae.
1) Cervical vertebra - has a pair of vertebrarterial canals, has thin centrum (plural: centra)
2) Thoracic vertebra - has long & backward/downward pointing neural spine, fairy large centrum, heart-shaped centrum.
3) Lumbar vertebra - thick & big centrum, short & broad neural spine, large & broad/flat transverse process.
4) refer pg 4 of yr notes.



• iii) the ribcage: (ribs & sternum)
  a) 12 pairs of ribs, articulate with the thoracic vertebrae at the back & join to the sternum in the front portion.
  b) ribs are flattened, curved bones.
  c) functions:
  1) protects the heart & lungs
  2) role in breathing.
  d) sternum is a flatenned, kite-shape bone, located at the anterior thoracic wall.

click here - to view animated human skeletal system

.... to be continued ....