HEALTH NOTES TOPIC 2_geet monga

SKELETAL SYSTEM:

The skeleton is the internal framework of the body. 

It is composed of 270 bones at birth, which is decreased to approximately 206 by adulthood after some fuse together.

Bones to know: 

-Cranium

-Mandible

-Clavicle

-Pelvis

-Fibula

-Ulna

-Calcaneus

-Cervical

-Sternum

-Phalanges (of the feet)

-Scapula

-Humerus

-Femur

-Tarsals

-Sacrum

-Coccyx

-Ribs

-Thoracic

-Radius

-Carpals

-Metacarpals

-Patella

-Metatarsals

-Lumbar

-Phalanges (of the hands)

-Tibia

Tips:

Fibula - think ‘fine’

Tibia - think ‘thick’ 

(bones in legs/body)

Radius - thumb side

Ulna - pinky side

Tarsals - ankles

Metatarsals - midfoot

Phalanges - toes

Carpals - wrist

Metacarpals - palm

Phalanges - fingers

Vertebrae:

-Small bones making up the spine

-Each vertebra increases in size as you move down from the head to the waist

-Each vertebra has a hollow centre through which the spinal cord passes

-The spinal cord relies on the vertebrae for protection.

Skeletal System Functions:

1. Allows movement

2. Shape and protection

3. Mineral storage

4. Production of blood cells

Allows movement:

The skeleton allows movement of the body.

Bones provide surfaces of the attachment of muscles.

Bones allow muscles to pull on them to produce movement.

Shape and protection:

The skeleton gives the correct shape to the body.

Bones protect the internal organs and reduce the risk of injury on impact.

• Rib cage protects the heart and lungs

• Cranium protects the brain

• Vertebra protects the spinal cord

Mineral Storage:

Bones store minerals such as calcium iron potassium and phosphorus

Minerals will be released into the blood when the body needs them

Production of blood cells:

Red and white blood cells are produced in the bone marrow (centre of most bones)

Red blood cells:

Carry oxygen to muscles

Are red in color due to haemoglobin

-Haemoglobin is a protein containing iron

Production is very high during growing years and decreases with age.

White blood cells: Fight against infection 

MUSCULAR SYSTEM:

Organ system, approx 600 muscles

Muscles to know:  trapezius, deltoid, pectoralis major, wrist flexors, hamstrings, gastrocnemius, soleus, tibialis anterior, quadriceps, hamstrings, biceps, triceps, latissimus dorsi, gluteus maximus, obliques, adductors, rectus abdominis, erector spinae, abductors 

Muscular system functions:

1. Create movement

2. Posture

3. Heat production

Create movement: 

Muscles are responsible for the movements we make.

Muscles pull on bones to produce movements. 

Posture:

Flexibility and strength are key to maintaining proper posture. 

Poor posture can lead to joint pain and weaker muscles. 

Heat Production:

When muscles contract (create movement), they generate heat. 

The heat produced is vital in maintaining body temperature. 

MUSCULOSKELETAL SYSTEM

Refers to bones, ligaments, tendons and skeletal muscles. The collaboration between the skeletal and the muscular systems gives the body its ability to move.

Ligaments: Fibrous tissue that connects bone to bone. Provide stability at the joint where the movement occurs. 

Tendons: Tough bands that connect muscle to bone. Muscles contract (shorten) and pull on tendons which pull on bones. The pulling on the bones is what creates the movement. 

Ligaments connect bone to bone WHEREAS tendons connect muscle to bone. 

Flexion: A movement that decreases the angle between the bones and a joint.

Extension: A movement that increases the angle between two body parts. 

Reciprocal Inhibition: Skeletal muscles work in pairs to enable movement. When one muscle contracts, its pair relaxes.

Agonist: Describes the muscle that contracts (shortens)

Antagonist: Describes the muscle that relaxes (lengthens).

CARDIOVASCULAR SYSTEM

Also known as the Circulatory system. Consists of heart and blood vessels working together to transport gases and nutrients around the body. 

Functions: 

1. Circulates blood around the body

2. Transports oxygen and nutrients to the cells

3. Transports wastes (carbon dioxide) away from the cells

4. Maintains stable body temperature

Blood Vessels: Types of blood vessels are capillaries, arteries and veins. 

Arteries: Generally carry oxygen-rich (oxygenated) blood. They always transport AWAY from the heart to the body. (Arteries, Away). They have elastic walls so that they can expand to accommodate more volume.

The aorta is the largest artery in the body. The left ventricle pushes blood into the aorta and onto the rest of the body. 

Capillaries: They are the smallest type of blood vessel. They are the site where nutrients and waste are exchanged between the blood and the body cells. This exchange is extremely fast because of the thin capillary walls. 

Veins: Generally carry blood with lower oxygen content and higher carbon dioxide content (deoxygenated blood). Always transports blood to the heart. Has thin walls and not as elastic as the walls of the arteries. They rely on skeletal muscles contracting to transport blood back to the heart. One-way valves prevent backflow of blood. 

The Heart: Pump designed to push blood throughout the cardiovascular system. Located slightly to the left of the chest, (between the two lungs). Protected by the rib cage. The adult heart is the size of a large fist. 

When looking at a heart, the left and right sides are opposite. 

The heart has 4 chambers (two atria and two ventricles);

• The atria are the upper chambers that receive blood.

• The ventricles are the lower chambers that pump blood.

The septum divides the heart into two sides; 

• The left has oxygenated blood for the body

• The right has deoxygenated blood that travels to the lungs for the removal of carbon dioxide. 

Heart rate: The number of times your heart beats in a given amount of time (usually a minute). At rest, the average heart rate is 72 bmp (beats per minute). Heart rate is measured by taking a pulse.

Heart beat: The sound when listening to the heart. 

Taking a pulse:

PATHWAY OF BLOOD

🫀 Pathway of Blood 

Right Atrium (Start)

• Receives deoxygenated blood from the body via the vena cava.
  
  

• Superior vena cava → from the upper body.
  
  

• Inferior vena cava → from the lower body.
  
  

2. Right Atrium → Right Ventricle
   
   

   • Blood moves from the right atrium into the right ventricle.
     
     

   • A valve opens to allow blood flow.
     
     

3. Right Ventricle → Pulmonary Arteries → Lungs
   
   

   • The right ventricle pumps blood through the pulmonary artery to the lungs.
     
     

   • A valve closes to prevent backflow into the atrium.
     
     

4. At the Lungs (Gas Exchange #1)
   
   

   • Carbon dioxide (CO₂) is removed.
     
     

   • Oxygen (O₂) is added → blood becomes oxygenated.
     
     

   • This process is called gas exchange.
     
     

5. Lungs → Pulmonary veins → Left Atrium
   
   

   • Oxygenated blood returns to the heart via the pulmonary vein.
     
     

   • Enters the left atrium.
     
     

6. Left Atrium → Left Ventricle
   
   

   • Blood moves from the left atrium to the left ventricle.
     
     

   • A valve opens to allow this.
     
     

7. Left Ventricle → Aorta → Body
   
   

   • The left ventricle pumps oxygenated blood through the aorta to the rest of the body.
     
     

   • A valve closes to prevent backflow.
     
     

8. Throughout the Body (Gas Exchange #2)
   
   

   • Blood delivers oxygen and nutrients to body cells.
     
     

   • Collects waste (CO₂).
     
     

   • Gas exchange happens in the capillaries.
     
     

9. Deoxygenated Blood Returns
   
   

   • Blood becomes deoxygenated and travels back to the heart through the veins.
     
     

10. Back to the Right Atrium
    
    

• Deoxygenated blood returns via the vena cava, completing the cycle.
  
  

RESPIRATORY SYSTEM

Includes the nose, mouth, throat, voicebox, windpipe and lungs.

Specialised for gas exchange.

Functions:

• Brings air from the atmosphere into the lungs

• Transfers oxygen from the air into the blood

• Removes carbon dioxide from the blood

• Expels heat in the air exhaled

• Allows the vocal cords to create speech as air is exhaled

The Lungs:

• The lungs are the major organ of the respiratory system.

• Lungs are located in the chest cavity behind the ribs

• Allow oxygen in the air to be taken into the body, while also letting the body get rid of carbon dioxide.

Alveoli:

• Are tiny air sac within the lungs

• The site where the lungs and blood exchange oxygen and carbon dioxide during breathing. 

The Diaphragm:

• Is a muscle of the respiratory system

• It helps to inhale and exhale.

Breathing:

• Is the process of taking air into and expelling it from the lungs

• Broken into two phases, inspiration and expiration.

Concentration:

• Breathing relies on the tendency of air particles to naturally move from areas of high pressure to areas of low pressure. 

Inspiration:

• Also known as inhalation

• The process where air is drawn into the lungs

Inspiration:

Step 1: The diaphragm muscle contracts, moving downwards

Step 2: The intercostal muscles contract, increasing the size of the chest cavity. 

Step 3: The pressure in the lungs decreases

Step 4: Air is drawn into the lungs as gases move from high to low pressure areas.

Expiration:

• Also known as exhalation

• The process where air is expelled from the lungs

Expiration: 

Step 1: The diaphragm muscles relax, moving upwards.

Step 2: The intercostal muscles relax, decreasing the size of the chest cavity

Step 3: The pressure in the lungs increases

Step 4: Air is forced out of the lungs as gases move from high to low pressure areas.

Gaseous Exchange:

• The process where gases move across a surface without the use of energy. 

• Between alveoli and the capillaries at the lungs

- Allows deoxygenated blood to become oxygenated

- Carbon dioxide moves from the capillaries to the alveoli. 

- Oxygen moves from the alveoli to the capillaries. 

• Between the capillaries around the skeletal muscles and muscle cells

- Oxygenated blood becomes deoxygenated.

- Carbon dioxide moves from the muscle cells to the capillaries. 

- Oxygen moves from the capillaries into the cells.