systems unit review

Types of circulation

Pulmonary circulation – pathway of blood from heart to the lungs and back

Cardiac circulation – route of blood WITHIN the heart

Systemic Circulation – route of blood from the heart to the body. It includes all the blood vessels other than those associated with the lungs

The circulatory (or cardiovascular) system has several functions:

Transportation of O2, CO2, wastes, nutrients, and hormones

Maintain body temperature

Maintain body fluid levels

Parts of the Mammalian Circulatory System

The Heart: a muscular organ that continuously pumps blood through the body, generating blood flow.

The Blood Vessels: a system of hollow tubes through which the blood moves.

The Blood: The fluid that transports nutrients, O2, CO2 and many other materials throughout the body.

Human Heart Anatomy

Cardiac muscle cells are arranged in a network that allows the heart to contract and relax rhythmically and involuntarily without becoming fatigued.

Location of the Heart

The heart is located in the chest cavity

Slightly behind and to left of sternum

Rib cage protects it

Human Heart Anatomy

Has four chambers

Atria: the two top chambers that fill with blood returning from the body or the lungs (singular atrium).

Ventricles: two bottom chambers that receive blood from the atria and pump it out to the body or the lungs.

Blood Flow in the Heart

The vena cavae bring oxygen-poor blood from the body to the right atrium.

The oxygen-poor blood flows from the right atrium into the right ventricle.

The right ventricle pumps the oxygen-poor blood to the lungs through the pulmonary arteries.

The pulmonary veins bring oxygen-rich blood from the lungs back to the heart through the left atrium.

Oxygen-rich blood flows from the left atrium to the left ventricle.

The left ventricle pumps the oxygen-rich blood to the body through the aorta.

Heartbeat “lub-DUB”

Valves prevent the blood from flowing backwards.

The “lub” sound is caused by the closing of the atrioventricular (AV) valves as blood is pumped from the atria to the ventricles.

The “DUB” sound is caused by semilunar valves, as blood is pumped from the ventricles into the arteries

Blood Vessel Layers

Vasa vasorum

“vessels of vessels”

Small blood vessels that supply oxygen to the layers of large blood vessels (i.e. aorta, vena cava)

Nervi vasorum

Nerve supply to large blood vessels

Allows regulation by the sympathetic nervous system

Major Veins & Arteries

Internal jugular vein

Subclavian vein and artery

Cephalic vein

Basilic vein

Inferior vena cava

Common iliac artery and vein

Great saphenous vein

Femoral vein

Renal vein

Renal artery

Common carotid artery

Brachial artery

Radial artery

Ulnar artery

Femoral artery

Aorta

Heart

3 Types of Capillaries

Least permeable - continous

Found in: fat, muscle, nervous tissue (most common)

More permeable - fenestrated

Found in: intestinal villi, endocrine glands, kidney glomeruli (tissues that specialize in fluid/molecule exchange)

Highly permeable - sinusoid

Found in: liver, bone marrow, spleen (where there is exchange of large proteins between blood and tissue)

Blood Introduction

Blood is a collection of cells that have been specialized to perform a set of tasks within an organism.

For this reason, doctors and scientists consider blood a tissue and not a fluid.

Blood consists of two distinct elements:

1.Plasma: the fluid portion of the blood (55% of blood)

2.Cells: the solid portion of blood (45% of blood)

Plasma

Fluid portion of the blood that carries blood cells.

Made up of 90% water, the other 10% made up of blood proteins, glucose, vitamins, minerals, dissolved gases, waste products of cell metabolism.

Also transports CO2.

Red Blood Cells

Erythrocytes
Make up about 44% of blood.

Specialized to transport oxygen; without RBCs, plasma could only carry about 2% of the normal oxygen load.

Have a biconcave disc shape, which increases surface area for oxygen exchange.

They contain no nucleus, live for about 120 days, and are constantly reproduced.

Average count: approximately 5.5 billion RBCs per mL of blood in males and 4.5 billion per mL in females.

Each RBC contains roughly 280 million hemoglobin molecules.

Hemoglobin is an iron-containing protein with four globin chains and one iron molecule, giving it a high affinity for oxygen.

Hemoglobin plus oxygen forms oxyhemoglobin.

RBCs lose their nucleus to maximize space for hemoglobin.

White Blood Cells

Make up about 1% of blood's volume.

Produced in bone marrow.

White blood cells contain nuclei and appear colourless.

They play many roles in fighting off infection and protecting the body from pathogens.

The number of WBC may increase by double when you are fighting off an infection.

Pus: fragments of remaining protein of the WBC and the invader.

Leukocytes and Lymphocytes

White Blood Cells:

• Two major disease-fighting types are leukocytes and lymphocytes.

Leukocytes (Macrophages):

• Engulf and digest pathogens.

• Part of the innate immune response, which provides a general defense against infection.

• Can pass through capillary walls to reach infected tissues.

Lymphocytes:

• Part of the acquired (specific) immune response.

• Recognize and remember particular pathogens.

• Provide targeted defense and respond more effectively if the same pathogen invades again.

Platelets

Are not cells.

Fragments of larger cells that broke apart in the bone marrow.

They contain no nucleus and break down relatively quickly.

They help the blood to clot and protect the body from excessive blood loss after an injury.

Blood Clotting

What stimulates a blood clot?

Injury to the vessel lining and contact of the blood with tissues outside the vessel

1. Blood will NOT clot until a blood vessel is broken. This is the trigger!

2. Substances released by broken blood vessels attract platelets to the site

3. As platelets collect, they rupture and release special chemicals that combine with other clotting agents to produce thromboplastin

4. As long as calcium ions are present in the blood, thromboplastin reacts with prothrombin to produce thrombin

5. Thrombin reacts with fibrinogen to produce fibrin

6. Fibrin forms mesh strands around the area of injury. This traps the escaping material and forms a clot.

What are white blood cells?

White blood cells, a.k.a. leukocytes, are responsible for protecting your body from infection via pathogens

WBC circulate in your blood and respond to injury or illness

What do white blood cells do?

Locate the site of infection and locate other white blood cells to come and help defend your body

Many white blood cells carry out phagocytosis – cell eating (engulf invader to protect you)

Once this WBC army arrives and fights, they produce antibodies for protection.

LOCATION of WBC

WBC are found all around in your blood and are able to travel through blood vessel walls

Appearance and size of wbc

-white blood cells are colorless --can appear as a very light purple to pink color when examined under a microscope and colored with dye-round shape with a distinct nucleus

Microscopic

14-16 µm in diameter

How are white blood cells formed?

White blood cell formation occurs in the soft tissue inside of your bones (bone marrow).

Types of WBC/Leukocytes- The macrophage

Innate immune response

Not specific

Respond FAST

Initiate other responses

Types of WBC/leukocytes

Neutrophils

•Help protect your body from infections by killing bacteria, fungi and foreign debris.

•Lymphocyte

Consist of T cells, natural killer cells and B cells to protect against infections and produce immune response proteins to help you fight infection (antibodies).

Eosinophil

Identify and destroy parasites, cancer cells and assists basophils with your allergic response.

Basophil

•Produces an allergic response like coughing, sneezing or a runny nose. Main soldier in allergic response

Monocytes

Defend body by cleaning up damaged cells.

Blood Pressure

Force of the blood on the walls of the arteries.

Normal BP 120/80 mm Hg; decreases as you move away from the heart.

Stroke Volume: volume of blood leaving heart (L)‏

Heart Rate: number of beats (contractions) per minute (bpm)‏

Normal BP 120 mmHg/80 mmHg

The top number is your systolic blood pressure. (The highest pressure when your heart beats and pushes the blood around your body.)

The bottom one is your diastolic blood pressure. (The lowest pressure when your heart relaxes between beats.)

Two factors determine BP:

1.Cardiac Output (CO): amount of blood pumped from the heart each minute = Heart Rate (HR) x Stroke Volume (SV)

–⇡ CO = ⇡ BP

–increase CO by  ⇡HR or ⇡ Stroke Volume (stronger heart)‏

2.Arteriolar resistance: diameter of the arteriole determines the amount of blood flow

–⇡ diameter = ⇣ BP

Blood Pressure Regulation

•Diameter of blood vessels regulated by the medulla oblongata.

•Vasoconstriction: nerve impulses cause muscle to contract, reducing diameter of vessel, reduces flow to tissue, increases pressure

•Vasodilation: nerve impulses cause muscles to relax, increasing diameter of vessel, increases flow to tissue, decreases pressure

The Cardiac Cycle

•A bundle of specialized muscle tissue, called the sinoatrial (SA) node, stimulates the muscle cells to contract and relax rhythmically.

•Also referred to as the pacemaker, because it sets the pace for cardiac activity

•Located in the wall of the right atrium.
•The SA node generates an electrical signal that spreads over the two atria and makes them contract simultaneously.

•As the atria contract, the signal reaches another node, called the atrioventricular (AV) node.

´1. Draw the correct passage of blood as it returns from the left leg through its journey all the way back

´2. What is the wall of muscle that separates the left and right side of the heart called

´3. What is the fluid filled membrane that surrounds the heart and protects from friction called?

´4. What side of the heart receives deoxygenated blood?

´5. What is the circuit called the carries blood to and from lungs and heart?

´6. These are able to supply heart muscle cells with oxygen and nutrients. If plaque builds up inside these, it causes chest pain/ angina which is treated with drugs or coronary bypass surgery. What structures are we discussing?

Left leg → inferior vena cava → right atrium → right ventricle → pulmonary arteries → lungs → pulmonary veins → left atrium → left ventricle → aorta → body

Septum

Pericardium

Right side

Pulmonary circuit

Coronary arteries

Pulmonary Circuit – Oxygenation Exception

Normally:

Arteries = oxygen-rich

Veins = oxygen-poor

Pulmonary circuit is the exception:

Pulmonary artery = oxygen-poor blood → lungs

Pulmonary veins = oxygen-rich blood → left atrium

Reason: lungs are where gas exchange occurs, so blood only becomes oxygenated after it reaches them.

Tunica Layers of Blood Vessels

1. Tunica Intima (or Tunica Interna)

Innermost layer

Smooth endothelium

Function: reduces friction for blood flow

2. Tunica Media

Middle layer

Made of smooth muscle and elastic fibers

Function: vasoconstriction and vasodilation (controls blood pressure and flow)

3. Tunica Externa (or Tunica Adventitia)

Outermost layer

Connective tissue

Function: protects vessel and anchors it to surrounding tissue

Organic Compounds

Compounds that contain CARBON are called organic.

Macromolecules are large organic molecules.

Also called POLYMERS.

Made up of smaller “building blocks” called MONOMERS.

Examples:

1. Carbohydrates

2. Lipids

3. Proteins

4. Nucleic acids (DNA and RNA)

Carbohydrates

Small sugar molecules to large sugar molecules.

Examples:

A. monosaccharide

B. disaccharide

C. polysaccharide

Monosaccharide

Monosaccharide: one sugar unit

Examples: glucose (C6H12O6)

deoxyribose

ribose

Fructose

Galactose

Disaccharide

Disaccharide: two sugar unit

Examples:

Sucrose (glucose+fructose)

Lactose (glucose+galactose)

Maltose (glucose+glucose)

Polysaccharide

Polysaccharide: many sugar units

Examples: starch (bread, potatoes)

glycogen (beef muscle)

cellulose (lettuce, corn)

Lipids

General term for compounds which are not soluble in water.

Lipids are soluble in hydrophobic (water hating) solvents.

Remember: “stores the most energy”

Examples: 1. Fats (Fatty acids)

2. Phospholipids

3. Oils

4. Waxes

5. Steroid hormones

6. Triglycerides

Six functions of lipids:

1. Long term energy storage

2. Protection against heat loss (insulation)

3. Protection against physical shock

4. Protection against water loss

5. Chemical messengers (hormones)

6. Major component of membranes (phospholipids)

Fatty Acids

There are two kinds of fatty acids you may see these on food labels:

1. Saturated fatty acids: no double bonds (bad)

2. Unsaturated fatty acids: double bonds (good)

Healthier fatty acids: unsaturated

State at room temperature: liquid (mostly)

Bonding: At least one double bond or more

Examples of food that contain FA’s:

Avocado, olive oil, natural PB

Proteins (Polypeptides)

Made of Amino acids (20 different kinds of aa) bonded together by peptide bonds (polypeptides).

Six functions of proteins:

1. Storage: albumin (egg white)

2. Transport: hemoglobin

3. Regulatory: hormones

4. Movement: muscles

5. Structural: membranes, hair, nails

6. Enzymes: cellular reactions

Four levels of protein structure:

A. Primary Structure

B. Secondary Structure

C. Tertiary Structure

D. Quaternary Structure

* Only in their tertiary and quaternary forms are they functional.

Nucleic acids

Two types:

a. Deoxyribonucleic acid (DNA double helix)

b. Ribonucleic acid (RNA-single strand)

Nucleic acids are composed of long chains of nucleotides linked

Nucleotides include:

phosphate group

pentose sugar (5-carbon)

nitrogenous bases:

adenine (A)

thymine (T) DNA only

uracil (U) RNA only

cytosine (C)

guanine (G)

TEETH

Begin the process mechanical digestion (breaking the food down into smaller more manageable pieces) to assist in swallowing;

chopping, tearing and grinding

Each tooth is designed to complete a specific task ex. Canine as pointed and sharp to help tear, molars are flat to grind.

TONGUE

plays the role of moving

the food around the mouth

Taste - papillae (upper surface of the tongue, house the taste buds that allow us to taste food)

5 taste bud categories – salty, sweet, sour, bitter, umami

UVULA

hanging from the middle of the back edge of the soft palate

prevents food from entering the nasopharynx (or nose) during swallowing

SALIVA

clear liquid secreted into the mouth by the salivary glands and mucous glands of the mouth

moistens the mouth and lubricates food

assist in the chemical process of starch digestion by the enzyme amylase

BOLUS

round mass of food that has been chewed to the point of swallowing

ESOPHAGUS

Tube connecting the pharynx to the stomach

approximately 24 cm long; lined with circular and longitudinal muscles which work to move food in ONE direction (down)

PERISTALSIS

symmetrical contraction of muscles which moves in a wave down the esophagus to help propel food through the digestive tract – uni-direction (one direction)

STOMACH

Muscular J shaped organ where food is temporarily stored while further chemical and mechanical digestion happens

walls are folded to allow distension

lined by gastric glands which secrete gastric juices that aid in chemical digestion (HCl, salts, enzymes, water and mucous) stimulated by the presence of food

mucus lines and protects the surface of the stomach from the acidic gastric juice

3 layers of muscle that relax and contract to churn stomach contents

CHYME

thick liquid of partially digested food mixed with gastric juices

CARDIAC SPHINCTER

muscular valve at the junction of the esophagus and the stomach; (top of the stomach)

controls the backflow of stomach contents back into the esophagus

PYLORIC SPHINCTER

muscular valve at the lower end of stomach at the entrance of the small intestine.

when closed helps keep the food in the stomach

DUODENUM - SMALL INTESTINES

(the first part of the small intestine; “C” shaped)

Chemical digestion of chyme begins here

Bile from the gallbladder and digestive juices from the pancreas mix in here.

JEJUNUM- SMALL INTESTINES

Follows the duodenum, approximately 2.5m long, contains many more folds than the duodenum

The lining of the jejunum is specialized for absorption

ILEUM SMALL INTESTINES

3m long, functions to absorb nutrients and to push undigested food into the large intestine

Mainly absorbs B12 and bile salts and anything left over that has not been absorbed

VILLI SMALL INTESTINES + MICROVILLI

tiny finger like projections that increase the surface area of the intestines.

MICROVILLI - each villi is in turn covered with many fine brush like microvilli that further increase the surface area

LARGE INTESTINE

absorb nearly 90% of water from the alimentary canal;

contains anaerobic bacteria to help digest undigested material;

leftover material is referred to as feces which is pushed by muscular contractions into the rectum for disposal

CECUM

the cavity in which the large intestine begins and into which the ileum opens; the appendix is an offshoot of the cecum

APPENDIX

finger like projection at the end of the cecum; no known function any longer

-vestigial feature

ACENDING, TRANSVERSE AND DESCENDING COLON

ASCENDING COLON - part of the large intestine that ascends from the cecum to the transverse colon

TRANSVERSE COLON - part of the large intestine that extends across the abdominal cavity and joins the ascending to the descending colon

DESCENDING COLON - part of the large intestine that descends from the transverse colon

RECTUM, ANAL CANAL AND ANUS

RECTUM - the final part of the alimentary canal where waste is stored before being eliminated

ANAL CANAL - the terminal part of the large intestine

ANUS - the excretory opening at the end of the alimentary canal

SALIVARY GLANDS` - Accessory Organs

PAROTID GLAND - the largest of the salivary glands located slightly below and in front of the 2 ears; a duct connects the gland to the oral cavity; produces the majority of saliva

SUBLINGUAL GLAND - small salivary glands located under the tongue that secrete saliva directly into the mouth through a series of pores

SUBMANDIBULAR GLAND -pair of glands located beneath the jaw which connect by a duct to the oral cavity;

LIVER- Accessory Organs

Located in the right upper quadrant just below the diaphragm

Produces bile, an alkaline substance which aids in digestion of fats acting as an emulsifying agent (breaks fat down into smaller fat droplets that are more readily absorbed)

Some of the bile drains directly into the duodenum

GALLBLADDER - Accessory Organs

Stores and concentrates bile produced by the liver and releases it through the common bile duct to the duodenum.

Attached on underside of liver

Humans can live without a gallbladder

PANCREAS - Accessory Organs

Glandular organ producing several important hormones, including insulin (used to move glucose from the blood into tissues) and glucagon (used to mobilize glucose from the tissues to the blood)

Secretes pancreatic juice containing digestive enzymes that pass to the small intestine and break down many macromolecules.

Enzymes

* Digestive enzymes help the body break down food.

* Different enzymes, each with specific functions, are produced in various parts of the digestive tract.

* Incomplete digestion can contribute to ailments such as:

* Flatulence, bloating, belching

* Food allergies, nausea, bad breath

* Bowel problems, stomach disorders

* Digestive enzymes mainly handle the chemical breakdown of food and make up a large part of digestive secretions.

* The human body produces around 22 different enzymes involved in digestion.

Mouth

Saliva contains the enzyme salivary amylase. This enzymes breaks starch into smaller sugars and is stimulated by chewing. It is important to chew food thoroughly as this is the first stage of the digestive process.

Stomach

The stomach is responsible for the digestion of protein and ionization of minerals. The parietal cells of the stomach secrete hydrochloric acid (gastric acid).

Pepsin is secreted by the stomach and breaks up proteins

Small Intestine

The small intestine has three segments and secretes various digestive substances.

It also receives enzymes and secretions from the pancreas, liver, and gallbladder.

Duodenum – primarily absorbs minerals.

Jejunum – absorbs water-soluble vitamins, proteins, and carbohydrates.

Ileum – absorbs fat-soluble vitamins, fats, cholesterol, and bile salts.

Pancreas

The pancreas produces digestive enzymes that act in the small intestine and play a major role in digestion.

It secretes about 1.5 litres of pancreatic juice per day.

Pancreatic enzymes include:

Lipases – digest fats, oils, and fat-soluble vitamins.

Amylases – break down starches and carbohydrates into smaller sugars like maltose.

Proteases – break down proteins into smaller amino acids.

Liver and Gall Bladder

The liver produces bile that is either stored by the gallbladder or secreted into the small intestine.

Bile emulsifies fats and fat-soluble vitamins.

It also helps keep the small intestine free from parasites.

The liver metabolises proteins, carbohydrates and cholesterol and is responsible for the detoxification of toxins, drugs and hormones.

Peptic Ulcers

Ulcers occur when stomach or duodenum tissues become inflamed due to a weakened mucous lining.

Most ulcers are caused by Helicobacter pylori, an acid-resistant bacterium that prevents mucus production.

Symptoms: abdominal pain, bloating, nausea, loss of appetite.

Treatment: antibiotics to eliminate bacteria and medications to reduce acid production.

Inflammatory Bowel Disease

Inflammatory bowel disease (IBD): general term for diseases causing intestinal inflammation.

Chronic conditions that cannot be cured but can be treated.

Crohn’s disease – can affect any part of the digestive tract

Symptoms: diarrhea, abdominal cramping, fatigue, blood in stool, reduced appetite

Treatment: medications to reduce signs and symptoms

Ulcerative colitis – affects the colon

Symptoms: loose/bloody stool, cramps, abdominal pain

Treatment: surgery to remove affected colon section, medications to reduce symptoms

Constipation

Bowel movements are reduced to 3 or less per week. Stools are dry, small and difficult to eliminate.

Can be caused by inadequate water intake, lack of physical activity or healthy diet, and lack of good nerve and muscle function in the bowel

Treatment: Increase hydration and fiber

Hepatitis

Hepatitis: inflammation of the liver; three types – A, B, and C.

Symptoms: fever, malaise, loss of appetite, diarrhea, nausea, abdominal discomfort, dark urine, jaundice (yellowing of skin/eyes).fever, mal

Treatment: no specific cure; manage symptoms.

Hepatitis C:

• Caused by the Hepatitis C virus, a bloodborne virus.

• Transmission:

• Sharing injection equipment (drug use)

• Reuse/inadequate sterilization of medical equipment (syringes/needles)

• Transfusion of unscreened blood products

• Vaccine: none available

Hepatitis A:

• Contracted from contaminated food or water.

• Vaccine: available

Hepatitis B:

• Potentially life-threatening liver infection.

• Transmission: infected bodily fluids

• Vaccine: available

Cirrhosis

Chronic disease of the liver that occurs when scar tissue replaces healthy liver tissue and prevents the liver from functioning properly.

Chronic alcoholism and hepatitis C are most common causes

Treatment: liver transplant

Gall bladder Stones

Cholesterol in the bile can precipitate out of the bile and form crystals. These crystals grow and become gall stones

Factors that can cause stones are obesity, heredity and alcohol intake

Can be treated with medications or ultrasound shock waves

If the gallstone problem is serious, the entire gall bladder may need to be surgically removed.

Common Procedures

• Barium swallow:

  • X-ray using liquid barium to visualize the esophagus and upper digestive tract (throat, esophagus, stomach)

  • Helps detect swallowing issues, blockages, ulcers, or tumors

• Endoscopy:

  • Medical procedure using an endoscope (thin, flexible tube with light and camera)

  • Can visualize:

    • Enzyme activity

    • Structure of digestive tract

    • Digestion in action

  • Can also remove polyps or take samples for biopsy

Maximizing the Efficiency of Respiration

All organisms need oxygen and must get rid of carbon dioxide.

Gas exchange requires special organs that connect the inside of the body to the outside and provide enough surface area for oxygen in and carbon dioxide out.

Respiration:

General meaning: taking in oxygen, releasing carbon dioxide.

Cellular respiration: oxygen is used by cells as the final electron acceptor to make ATP, producing carbon dioxide as a waste product.

Gas Exchange in Animals

Respiration & Gas Diffusion:

Gases diffuse across plasma membranes.

Oxygen must dissolve in water to cross membranes.

Plasma membranes are surrounded by water, so oxygen from air dissolves in this layer.

Primitive invertebrates:

No special respiratory organs.

Keep respiratory surfaces moist to allow gas exchange.

Example: Earthworm

Gills as Respiratory Structures

Aquatic respiratory organs increase the diffusion surface area by extensions of tissue called gills

External gills increase surface area, but the organism must always be kept moving because oxygen in stagnant water can be quickly depleted.

The external gills are easily damaged

Gills

Evaginated structures (body outgrowths) with large surface area for gas exchange.

Circulatory system inside gills carries oxygen away and removes CO₂.

External gills: unprotected (e.g., Polychaete worms).

Internal gills: protected (e.g., fish).

Respiration in Amphibians

Gas exchange in unique organisms:

Two ways: lungs and skin.

Amphibians:

Lungs: force air in by creating higher pressure outside lungs.

Air fills buccal cavity → nose & mouth closed → floor of mouth raised → air pushed into lungs.

Skin: must stay moist for diffusion.

Important during hibernation, e.g., buried under mud in ponds.

Respiration in Mammals

Mammals have higher metabolic rates to produce and sustain their body temp and thus require a more efficient respiratory system

Lungs of mammals are packed with million of tiny air sacs called alveoli providing an enormous surface area for gas exchange

Flow of Air

Air is brought into the alveoli through a system of passages:

Mouth/Nose → pharynx → larynx → trachea → bronchi → bronchioles → alveoli

Features of the respiratory system

Nostril – conducts air into hollow nasal cavity.

-best way to intake air as it cleans and purifies air

Nose Hair

Nose hairs help to filter out dust and dirt particles from entering the respiratory tract

Hairs are covered in mucus that trap particles as they are breathed in

Turbinates

Thin bones found in the nasal cavity that increase surface area and secrete mucous (Goblet cells).

This helps to moisten the air.

The turbinates are lined with capillaries that warm and increase humidity of incoming air.

Ciliated Cells

– These cells secrete mucous.

The mucous traps the foreign particles.

Continual sweeping of the cilia propels these particles back to the nose and throat where they can be expelled.

Main type of ciliated cell = goblet cell

Goblet Cells

Epithelial cell that has a primary function in creating and secreting mucus.

Sinuses

Main function is to produce mucus that moisturize and humidifies the inside of the nose.

The mucus layer protects the nose from pollutants, micro-organisms, dust and dirt

Pharynx

Pharynx- connects the nose and mouth to the throat. This is broken into several different areas.

Epiglottis

Glottis – opening to the trachea

Epiglottis – flap of cartilage located behind the tongue that helps prevent food from entering trachea

Snaps shut when swallowing

Larynx

Larynx – houses the vocal cords.

There are two folded structures of the vocal cords.

When you breathe normally there is a large gap between the cords.

When you speak, muscles contract bringing cords closer. The air that passes through them vibrates the cords producing sound.

Trachea

Trachea – Flexible tube that is the passageway of air.

Supported by semi-circular cartilage rings to ensure it does not collapse from the passage of food in the esophagus.

lined with ciliated goblet cells that secrete mucous.

Bronchi

Bronchi – 2 smaller branches of the of the trachea leading to the left and right lung

Bronchioles – tiny subdivisions of the bronchi

Alveoli

Alveoli – grape like clusters of tiny sacs at the end of the bronchioles.

These sacs are always kept moist.

This is the site of gas exchange.

The sacs provide an abundance of surface area for the exchange of gases.

They are surrounded by capillaries.

Lungs

Lungs:

Flexible membranes that expand and contract.

Right lung: 3 lobes | Left lung: 2 lobes.

Contain bronchi, bronchioles, and alveoli.

Pleura:

Tissue layer that envelops lungs.

Flexible, allows expansion/contraction.

Each pleura has two layers separated by lubricating fluid.