Human physiology

Lesson 1.


Digestive system.


Mouth.

What happens in the mouth?


  • The food is chewed

    • Teeth and tongue grind the food inte smaller pieces

      • easier to swallow

  • mix the food with saliva (amylase - enzyme)

  • Amylase - enzyme, digest starch into maltose

Food -> bolus


Oesophagus

  • Ball of food pressed against the pharynx -> swallow reflex

  • Swallow reflex

    • muscles contract elevating the larynx

      • closing epiglottis

  • Muscles in the wall of the esophagus starts to contract

    • pushing the food towards the stomach

  • App 10 sec

  • Cardiac sphincter connects esophagus and stomach



Stomach

  • App 2 litres

  • Two functions

    • Reservoir for ingested food (1-2 hours)

    • Digestion

  • Thick and muscular wall

    • Mixing and grinding food -> increased surface area

    • contains gastric glands producing gastric juice

      • Hydrochloric acid -> pH ≈ 2

      • Pepsin - enzyme, polypeptides -> smaller polypeptides

      • Mucus - protection against acid and enzyme

-> Chyme


  • Pyloric sphincter connects stomach and small intestine


Small intestine

  • Two important functions

    • Digestion and absorption

Duodenum

  • Chyme is mixed with pancreatic juice

  • Pancreatic juice

    • Hydrogen carbonate - neutralizes the acid from the stomach

    • lipase enzyme, digest lipids into glycerol and fatty acids

    • Amylase - enzyme, digest starch into maltose

    • Trypsin - enzyme, digest polypeptides into amino acids

  • Bile - Yellow fluid produced by the liver

    • Stored in the gallbladder

    • Emulsify lipids -> increase of surface area

  • Complete digestion of food

  • Peristalsis moved the food

  • Absorption of nutrients into the circulatory system-

  • Has a very large surface area

    • Villi

    • Microvilli

    • Many mitochondria (to make ATP to move proteins into vessels)

    • Short distance to vessels of circulatory system

      • (necessary for diffusion)



Colon - large intestine

  • Absorption of water

  • No digestion or absorption of nutrients

  • inhabited by bacteria - produce vitamin B and K

  • Constipation - Fibres, drugs

  • Diarrhea - water absorption is hindered


Rectum

  • Feces accumulate

  • Defecation/egestion

    • Stretch receptors

    • Sphincter relax

      • Defecation

  • 12-24 h



Lesson 2.


  • Ventilation - breathing in and out

  • Gas exchange - swapping one gas for another

  • Cell respiration - release of energy in the form of ATP


Why do we need gas exchange?


  • We need to take in oxygen and excrete carbon dioxide in cellular respiration

  • Unicellular organisms utilize diffusion for this


Types of ventilation systems.


  • Lungs

  • Gills

  • Tracheal system

  • Skin


  • Nasal cavity

    • Filtrating, heating and moisturizing air

    • Hair and mucus membranes

  • Pharynx

    • Air from nasal cavity and mouth meet

  • Trachea

    • Made of horseshoe-shaped rings of cartilage

    • Mucus

    • Cilia

  • Bronchi

    • Left and right bronchus

  • Bronchioles


Alveolar sac


  • At the ends of each bronchiole

  • Adult lung - 300 - 500 million alveoli

    • SA of 75m^2 - 100m^2

  • Thin walls

  • Surrounded by a network of capillaries

  • Covered in a layer of moisture

  • Gas exchange


Oxygen  transport by blood


  • Transported by haemoglobin found in red blood cells


Ventilation


  • Inspiration - inhalation

  • Diaphragm and external intercostal muscles contract

  • Diahpragm moves down and ribcage moves up and out

    • Volume of thoracic cavity increase

    • Air pressure inside lungs decrease


  • Expiration - exhalation

  • Passive or active

  • Diaphragm relaxes, internal intercostal muscles and abdominal muscles contract

  • Diaphragm moves up and ribcage moves down and in

    • Volume of thoracic cavity decreases

    • Air pressure inside lungs increases

    • Air flows out the lungs


  • Ventilation rate

    • At rest : 10-15 breaths/min

    • exercise : 60 breaths/min

  • Ventilation rate controlled by the respiratory centres in the brain

  • Receptors are sensitive to carbon dioxide levels


Diseases connected to the respiratory system


  • Emphysema

  • Bronchitis

  • Asthma

  • Pneumonia

  • Tuberculosis

  • Cancer


Rate : change overtime


Lesson 3.


Why do we need the cardiovascular system?

  • All the cells of the body are connected

  • We are too big to depend on diffusion for transport


What is transported with the cardiovascular system?

  • Oxygen, nutrients, hormones, enzymes, urea, carbon dioxide and heat


Components

  • Heart

  • Blood

  • Vessels

    • Arteries

    • Veins

    • Capillaries


The Heart

  • A muscular pump

  • Moves blood through the body

  • Surrounded by a pericardium

  • Composed of four chambers

  • Divided into a left and a right half

  • Made of cardiac muscle

  • Coronary arteries


Structure of the heart

  • Chambers

    • Atria (2) - upper chambers

    • Thin

    • Receives blood from veins

    • Sends blood to ventricles


  • Ventricles (2) - lower chambers

  • Receives blood from the atria

  • Pumps blood into arteries


  • Valves - prevents backflow


Pathway of circulation

  • Arteries branch into smaller and smaller vessels (arterioles)

  • They eventually become capillaries, which supply blood to all body parts

  • Capillaries merge into vessels (venules) which join into veins and carry blood back to the heart


Blood Vessels - Arteries

  • Arteries

    • Recieve blood from ventricles

    • Take blood away from the heart

    • Thickest vessel walls

    • Withstand greater blood pressure

    • are very elastic

    • connect to capillaries

    • Aorta is the largest artery


Blood Vessels - Veins

  • Veins

    • Transport blood away from capillaries

    • Carry blood toward heart

    • Take blood to atria

    • Have valves

    • Thinner vessels walls with less smooth muscles than arteries

    • Can stretch a great deal

    • Have larger diameters

    • Vena cava is the largest vein


Blood Vessels - Capillaries

  • Capillaries

    • Smallest of blood vessels

    • Only one cell thick (epithelial cell)

    • Connect arteries to veins

    • Bring oxygen and nutrients to cells

    • Remove carbon dioxide, urea, and other wastes from cells.


Plasma

  • 90% water

  • Proteins e.g. antibodies, albumin

  • Salts

  • Minerals

  • Dissolved gases

  • Nutrients

  • Hormones

  • Enzymes

  • Waste

  • Vitamins


Red blood cells

  • Erythrocyte

  • Produced in the bone marrow

  • Biconcave disks -> increase SA

  • No nucleus

  • Contains haemoglobin

  • Life span about 120 days

  • Destroyed in the liver - iron recycled

  • EPO

  • Anaemia


White blood cells

  • Leukocyte

  • Have nucleus

  • Protect body against infection

  • many different forms

  • Life span varies (3 days - a month)

  • Number increase of an infection is present


Platelets

  • Thrombocyte

  • No nucleus

  • Life span about 7 - 11 days

  • Have a sticky surface

  • Responsible for blood clotting


Blood clotting

  • Vessel is broken

  • Blood leaks out

  • Platelets turn fibrinogen into fibrin

  • Net of fibrin over the cut

  • REd blood cells get stuck

  • -> scab

How to measure heart rate

  • Measure pulse

    • Neck

    • Wrist

  • Steothoscope










Lesson 4.


Pathogen


  • an organism or virus causing a disease


types of pathogens

  • viruses

  • bacteria

  • fungi

  • protozoa

  • worms


Transmission of pathogens

  • Airborne

  • Waterborne

  • Foodborne

  • Vectorborne

  • Sexually transmitted

  • Direct contact


Preventing infection


What can we do to prevent infection?

  • Wash your hands

  • clean teeth

  • wash cuts and scratches

  • food

  • water


Destruction of pathogens


How can we kill pathogens outside the body?

  • heating

  • radioactivity

  • disinfectant

  • antiseptics


Non-specific immune system

  • Prevent or destroy a variety of pathogens regardless of pathogen type

    • Prevent entry into the body

    • Quickly destroys an invader if it gets in

      • Surface protection

      • Phagocytosis



Surface protection

  • The skin

    • unbroken

    • lactic acid and fatty acids

    • Commensal bacteria

  • Mucus membrane

    • Line body cavities

    • Mucus

    • Lysozyme

    • Cilia

    • Acid


Phagocytosis


Specific immune system

  • Can distinguish between self and non-self

  • Antigen - recognition device found on the surface of cells, binds to antibodies

  • Antibody - produced by lymphocytes as a response to an invasion


Antibodies

  • Proteins

  • Action of antibodies

  1. Antigen - antibody comple

  2. Neutralize the antigens ability to harm

  3. Can cause foreign cells to rupture


Immunity

  • Natural immunity

    • Passive

      • Antibodies from mother to fetus via placenta

      • Antibodies from mother to baby via breast milk

    • Active

      • When the immune system forms memory cells

      • The immune response at the second encounter with the antigen will be faster

  • Artificial immunity

    • Passive

      • Antibodies are given with an injection to help a patient to fight of a disease

    • Active

      • Vaccination

      • An antigen is given to a person to stimulate the person's own immune system, creating memory cells


Lesson 2.


Reproduction

  • Asexual reproduction

    • One parent

    • Offspring identical to parent

    • Tex. Amoeba, yeast, shoots.

  • Sexual reproduction

    • Two parents

    • Parents have sex organs

    • Sex organs produce gamets (sex cells)

    • Fusion of gametes -> zygote -> embryo

    • Variation in offspring


Sex cells


Sperms

  • Small

  • Swim using tail

  • No food store

  • Millions produced

  • Production all the time


Eggs

  • Large

  • Can not move much

  • Have a food store

  • Much fewer made

  • One a month


Female reproductive system

  • Ovaries - female sex organs

    • Produce female gametes

    • Produce progesterone and oestrogen

      • Production starts at age 10-15

      • Puberty

        • Changes in the body, e.g. breast, hair, period


Male reproductive system

  • Testis - male sex organs

    • Produce male sex gamets

    • Produce testosterone

      • Production starts at age 11-16

      • Puberty

        • Changes in the body, e.g. deeper voice, hair, muscles