Topic no.3 human body systems (dip) part 1

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Human Body SystemsLearning ObjectivesBe able to :1. Identify 5 body cavities and major

structures in each cavity.2. Identify 8 body systems and major

structures in each system.3. Describe the primary functions of body

systems.4. Understand how body systems work

together.

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Cells & Tissues

Mitochondria: Power house

Centrioles: Spindle fibres that move chromosomes around when cell is dividing.

Lysosomes: Membrane bags with digestive enzymes.

Golgi Bodies: “Packaging & shipping”bodies –they mend the cell membrane.

Vacuole: a storage bubble in the cytoplasm

Ribosomes: help make proteins;translate genetic code.

Endoplasmic reticulum or ER : transport proteins.

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5 major human body cavities

Cranial cavity

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5 major human body cavitiesBody Cavity Organs

Cranial Cavity BrainProtected by skull.

Spinal Cavity Spinal CordProtected by vertebrae.

Thoracic Cavity Lungs and heartProtected by rib cage & spine

Abdominal Cavity

Liver, pancreas, stomach, spleen, kidneys and intestines. Located between the diaphragm and the pelvis.

Pelvic Cavity Bladder, rectum and reproductive organs.Partially protected by pelvic bones & lower portion of spine.

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Human Body SystemsBody is made up of billions of cells .

Each cell is the basic unit of all living tissue. Different types of cells perform different functions.

Collections of similar cells form tissues, which form organs.

A body system consists of a group of organs and other structures that are specially adapted to perform specific body functions.

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Type of tissue Function Where found?

1. Epithelial tissue

Membranes lining organs •Outer layer of skin• Tissue surrounding organs• Inside of mouth & stomach

2. Connective tissue

Its fibrous strands of proteins of collagen add support and structure to body

• Inner layers of skin• Tendons, ligaments• Cartilage, bone and fat tissue

3. Muscle tissue a specialized tissue that can

contract to effect movement • Muscles of body

4. Nerve tissue Nerve tissue has the ability to generate and conduct electrical signals in the body. 

These electrical messages are managed by nerve tissue in the brain and transmitted down the

spinal cord to the body.

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Human Body SystemsFor our body to work properly, all the eight body systems must work in harmony.

1. Respiratory system2. Circulatory system3. Nervous system4. Musculoskeletal system5. Endocrine system6. Digestive system7. Genitourinary system8. Integumentary system

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1. Respiratory SystemOur body’s need for continuous supply of oxygen to stay alive is provided by the respiratory system through breathing.The respiratory system includes the lungs, pathways (airways) connecting them to the outside environment, and structures in the chest involved with moving air in and out of the lungs. An average adult breathes about 12 times per minute while awake or asleep (inhaling in 500 ml of air per breath). The purpose of moving so much air in and out of the body is to enable the lungs to do 2 things –To take in the oxygen needed to sustain life.To rid the body of the carbon dioxide – the waste product of

internal chemical processes.

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Respiration

Composition Inhaled Air Exhaled Air

Oxygen 21% 16%

Carbon Dioxide & inert gases

1% 5%

Nitrogen 78% 78%

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1. Ethmoid sinus 2. Maxillary sinus 3. Superior concha 4. Superior meatus 5. Middle concha 6. Middle meatus 7. Inferior concha 8. Inferior meatus 9. Nasal septum

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Respiratory SystemAir enters through the nose and mouth, and travels down the pharynx (back of throat) to enter the larynx (voice-box). The entrance to the larynx is protected by a muscular flap (epiglottis), which closes during swallowing to prevent aspiration of food.1. As air enters the nose, larger airborne particulates are trapped by the coarse hairs of the nostrils. The air is then warmed & moistened by the mucous membrane lining (all the way downto the alveoli) as it passes through the nasal cavities into the pharnyx and down to the larnyx. 2.Air breathed in through mouth is drier, colder and less clean.

Air then enters the trachea (wind-pipe). From here, it goes into the right and left primary bronchi ,down into the secondary bronchi, which branch into the bronchioles.

Right lung has 3 lobes while the left lung has 2 lobes.

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Respiratory System

Gas exchange takes place between the alveoli and the capillaries in the lungs.

Bronchioles are repeatedly branched into terminal bronchioles which carry air to the exchange levels of the lungs – the alveolar sacs (alveoli). Alveoli are covered by a thin film of moisture to protect their delicate tissues.

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Respiratory Protection System Physical Filtration1. Large airborne particulates are trapped by the moist hairs

in the nose and nasal sinuses, and subsequently washed out.2. As air travels through the twists and bends of the nasal cavity

airborne particulates collide with the sticky mucus lining and become trapped. They are then washed down the pharynx, where they are either swallowed or coughed out.

3. Sneezing occurs if airborne dust concentrations are high or have irritant effects.

4. The repeatedly branching of airways from the lower end of trachea down to bronchioles with gradual narrowing of their lumen slows down the airflow allowing some particulates to sediment on the mucus lining, and subsequently propelled by the cilia in constant motion up the pharynx to be swallowed or coughed out.

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Efficiency of the Filtration System

Depends of the sizes of the particulates. The smallest size of a particulate that can be seen by our naked eyes is 25 μm

Nose & nasal sinuses

Particulates 10 to 100 μm (diameter) can be removed

Particulates <10 μm can pass through.

Trachea to terminal bronchioles

Particulates up to 7 μm can be removed.

Alveoli Particulates ranging from 7 μm to 0.5 μm may be deposited.

Particulates < 0.5 μm may be exhaled out to the outside environment or may be deposited in the alveoli by diffusion.

Note: Particulates with size-range 7 μm to 0.5 μm is termed as the respirable dust.

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Biochemical Clearance When particulates become deposited in the

alveoli, it activates our defensive mechanism. This involves the movement of granulocytes (white cells) from the blood into the alveoli.

These amoeba-like cells are called phagocytes.

Phagocytes engulf foreign bodies and neutralise their harmful action. If the material is inert, phagocytes will move them to a lymph gland or out of alveoli to be cleared by the ciliary escalator.

Certain dusts that are not ‘inert’ kill the phagocytes. When this occurs tissue cells (alveoli) are damaged (inflammation & scarring)

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Class Discussion Exercise As an adult, how many times do we breath in air per

minute while at rest or asleep? How much air (in millilitres, mls) do we breathe in per breath?

What is the main function of our lungs? What is the function of epiglottis? How do our respiratory system prevent airborne

particulates from entering into the lungs? Particulates of sizes PM10 and PM2.5. Which one can

travel a longer distance in air, and which one is more harmful to our human body?