Unit 4 - Anatomy

Question 1

What are the four major functions of the human digestive system?

Answer 1

ingestion: the taking in of nutrients

digestion: the physical and chemical breakdown of complex food molecules into smaller molecules

absorption: the transfer of digested nutrients from the digestive system to the bloodstream

egestion: the removal of waste food materials from the body

Question 2

What are the two types of digestion?

Answer 2

1) Mechanical: breaks substances down physically into smaller pieces

2) Chemical: the breakdown of substances by enzymes and acids into their components

Question 3

What does the mouth do in digestion?

Answer 3

mechanical and chemical breakdown

Question 4

Explain the teeth and their role in digestion

Answer 4

Location: mouth
Digestion: mechanical
incisors (8): cutting and biting
canines (4): ripping and tearing
molars (20): grinding (8 premolars, 8molars, 4 wisdom teeth/third molars)

Question 5

Explain the tongue and its role in digestion

Answer 5

Location: mouth
Digestion: mechanical
-a muscle (one of the strongest in the body)
-helps with chewing, speech, and swallowing

-taste → taste buds have nerve endings which send a message to your brain

Question 6

Explain the salivary glands and their role in digestion

Answer 6

Location: mouth
Digestion: mechanical and chemical
parotid, submaxillary, sublingual

-contains enzymes that increase the rate of chemical reactions, water, and mucous
-contains the enzyme amylase that begins the breakdown of starch
-saliva also moistens the food (mechanical)

Question 7

Explain the pharynx and its role in digestion

Answer 7

Digestion: mechanical
a muscular tube that helps food along

Question 8

Explain the epiglottis and its role in digestion

Answer 8

Digestion: no digestion
-a flap of cartilage that covers your trachea when you swallow to prevent choking

Question 9

Explain the esophagus and its role in digestion

Answer 9

Digestion: mechanical
-muscular tube connecting the pharynx to the stomach
-peristalsis (wave-like muscle contractions) facilitates the movement of food down this tube

Question 10

Explain the stomach and its role in digestion

Answer 10

Digestion: mechanical and chemical
-the gastroesophageal sphincter prevents food and acid from moving up the esophagus

-special cells secrete hydrochloric acid and enzymes
-it is lined with special mucus-secreting cells, which prevents the stomach from “eating” itself with its own acid

-The stomach is made of smooth muscle which contracts and mixes the food until it’s in a semi-liquid state called chyme.

-The pyloric sphincter prevents food from leaving the stomach prematurely and controls the entry into the small intestine.

-proteins are partly digested in the stomach and continue digestion in the small intestine, lipids and carbohydrates are not digested in the stomach

Question 11

What are the four layers of the stomach?

Answer 11

mucosa: innermost layer, extensively
folded, secretes gastric juice (mixture
of digestive enzymes, acid and mucus),
its epithelial cells divide rapidly to heal
any damage

submucosa: the layer of connective tissue that contains networks of nerves and blood vessels, these nerves detect when food is present and initiate the release of a hormone called gastrin (stimulates the release of gastric juice)

muscularis or muscle layers: consists of smooth muscles that contract frequently, churning and mixing the
food with gastric juices to produce chyme

serosa: smooth, outermost layer
that holds the stomach in place and
secretes a lubricating fluid that
eliminates friction between organs

Question 12

What do gastric juices in the stomach do?

Answer 12

gastric juice kills many harmful microorganisms that are ingested with the food, stops the action of amylase, but provides the necessary pH for the activation of other digestive enzymes, such as pepsinogen

the hydrochloric acid present in the gastric juice converts pepsinogen to its active form, pepsin, which begins the breakdown of proteins into separate amino acids

Question 13

Explain the liver and its role in digestion

Answer 13

Digestion: mechanical
-it produces bile which is a highly basic substance that helps neutralize the chyme from the stomach
-bile also acts as an emulsifier (the body’s detergent), which helps it break down fat into smaller droplets so that digestive enzymes can act on this nutrient more efficiently

Question 14

Besides producing bile, what else does the liver do?

Answer 14

-it regulates the level of glucose in the bloodstream

-it converts excess glucose into glycogen or fat

-it removes ammonia (NH3) and turns it into urea, which is mixed with water to form urine

-produces cholesterol and blood clotting agents

Question 15

Explain the gall bladder and its role in digestion

Answer 15

Digestion: no digestion
-stores bile that is made in the liver
-drips bile into duodenum as food passes by
-helps to deodorize the stool (reduces the action of bacteria)

Question 16

Explain the pancreas and its role in digestion

Answer 16

Digestion: chemical
-produces bicarbonates which function as antacids and help control the pH of the duodenum
-produces many digestive enzymes
-produces hormones such as insulin

Question 17

Explain the small intestine and its role in digestion

Answer 17

Digestion: chemical
-7 meters long
-it completes the process of chemical digestion
-contains finger-like projections called villi that are responsible for absorbing nutrients into the bloodstream
-the villi hang from the wall of the small intestine and cover its entire surface
-peristalsis moves material through the small intestines

Question 18

What two characteristics make the small intestine ideal for absorbing nutrients?

Answer 18

The characteristics of the small intestine that make it ideal for absorbing nutrients:
A) length – because it is long, the nutrients have time to be absorbed

B) the walls of the small intestine have tremendous surface area due to:
the lining has folds: increase surface area by 3X
folds are covered in tiny villi: increase surface area by 10X
microvilli on the surface of the villi: increase surface area by 20X

Question 19

What are the three sections of the small intestine?

Answer 19

the duodenum, the jejunum, the ileum

Question 20

What happens when absorption occurs within the small intestine?

Answer 20

-monosaccharides (product of carbohydrate digestion), amino acids (product of protein digestion), and water-soluble minerals are absorbed into a network of capillaries that carry these nutrients from the vilus to an artery for transport through the circulatory system

-glycerol and fatty acids (products of lipid digestion) and fat-soluble minerals are absorbed into a lacteal that carries these nutrients through the lymphatic system

-most of the absorption of nutrients has occurred by the time the food reaches the jejunum

Question 21

Explain the large intestine and its role in digestion

Answer 21

Digestion: no digestion
-a one-way valve called the ileo-caecal sphincter prevents food from moving backwards into the small intestine

-fibre enters the large intestine along with waste
-peristalsis moves the waste into the rectum and then the anus where it is eliminated

-main function is to absorb water*

Question 22

What is the air we breathe?

Answer 22

The air we breathe is a mixture of different gases: 78% nitrogen, 21% oxygen, 1% argon, 0.04% carbon dioxide, and lesser amounts of other gases.

Question 23

What process allows oxygen to obtain energy from food?

Answer 23

aerobic cellular respiration
C6H12O6 + 6O2 → 6CO2 + 6H2O + energy
(glucose + oxygen → carbon dioxide + water + energy)

Question 24

Where does gas exchange in humans and other mammals occur?

Answer 24

the lungs and the body cells.

Question 25

Explain the nasal passages and their function in the respiratory tract

Answer 25

NASAL PASSAGES: (filter, warm, and humidify) -narrow and winding with many grooves -coarse hairs filter out dust particles and pathogens -blood vessels help to warm the air -mucous helps to moisten the air -particles are swept to the mouth (and then swallowed) by the beating cilia

Question 26

Explain the trachea and its function in the respiratory tract

Answer 26

-rigid with rings of cartilage that prevent it from collapsing -is lined with cilia, which move mucous and debris up and away from the lungs -divides into two bronchi which divide further into smaller-diameter bronchioles -the amount of cartilage decreases and smooth muscle increases as the tube diameter decreases

Question 27

Explain the lungs and their function in the respiratory tract

Answer 27

-humans have two lungs (the right lung has 3 lobes, left lung has 2 lobes) -the heart, large blood vessels, and the esophagus is found between the lungs -a membrane called the pleura covers the outer surface of the lungs and is lubricated by a thin film of liquid -pleurisy is the inflammation of the pleura

Question 28

What is pneumothorax?

Answer 28

A pneumothorax occurs when air leaks into the space between your lung and chest wall (pleura). This air pushes on the outside of your lung and makes it collapse.

Question 29

What does the lung tissue consist of?

Answer 29

-lung tissue is not dense but is much like a sponge that contains alveoli -alveoli are tiny, hollow, elastic sacs (think a cluster of grapes) -the walls of the alveoli are only one cell thick and lined with capillaries (tiny blood vessels – one cell thick) that allow gas to be exchanged between the lungs and the blood -there are approximately 100 000 000 alveoli per lung -alveoli greatly increase the surface area of the lung tissue

Question 30

Explain the alveoli and their site of gas exchange

Answer 30

OXYGEN (O2) –moves from the lung tissue to the blood CARBON DIOXIDE (CO2) –moves from the blood to the lung tissue → gases move by the process of diffusion

Question 31

Explain the control of breathing

Answer 31

Breathing is involuntary. -It is controlled by the nervous system and the circulatory system -We can temporarily, consciously control our breathing (holding our breath, talking, singing).

Question 32

What is the medulla oblongata?

Answer 32

a part of the brain that monitors the amount of CO2 in the blood (through the pH of the blood)

Question 33

How does the medulla oblongata operate?

Answer 33

-An increase in aerobic cellular respiration increases the amount of carbon dioxide in the blood, which in turn produces carbonic acid and lowers the pH of the blood. -Receptors in the medulla oblongata detect the lower pH and send nerve signals to the diaphragm and external intercostal muscles to initiate faster/more forceful movement.

Question 34

What is our rate of breathing determined by?

Answer 34

the demand for oxygen or the need to eliminate CO2 -the O2 and CO2 levels in the blood are constantly monitored by chemical receptors in the brain, in the arteries leading to the brain, and the arteries leaving the heart

Question 35

Describe and explain the breathing in movements and what occurs in the body

Answer 35

Inhalation/Inspiration (breathing in) 1) Rib muscles (external intercostals) contract, moving the ribs up and out; diaphragm contracts and flattens. 2)The volume of the lungs increases. 3)Pressure in the lungs decreases. 4) Air rushes into the lungs to equalize pressure.

Question 36

Describe and explain the breathing out movements and what occurs in the body

Answer 36

Exhalation/Expiration (breathing out) 1) Rib muscles (external intercostals) relax, moving ribs down and in; diaphragm relaxes and becomes dome-shaped (moves upwards). 2) Volume of lungs decreases. 3) Pressure in the lungs increases. 4) Air rushes out of the lungs to equalize the pressure.

Question 37

What is the diaphragm?

Answer 37

-muscle located below the lungs that creates more space in lung cavity to flatten and fill with air, or relax and allow air out -facilitates movement of air in and out of the body

Question 38

Explain gas exchange and transportation of oxygen in the respiratory tract

Answer 38

-Oxygen is not very soluble in blood but some does dissolve in the plasma. -Hemoglobin (Hgb), found in the red blood cells greatly increases the carrying capacity of the blood *hemoglobin contains 4 iron (Fe) atoms *iron provides the binding sites for O2 *280 million hemoglobin molecules per red blood cells -Hemoglobin is more attracted to CO (carbon monoxide) than O2, thus if both are present in inhaled air, hemoglobin will fill its sites with CO first -Carbon monoxide can be found in car exhaust and cigarette smoke (a product of incomplete combustion).

Question 39

Explain gas exchange and transportation of carbon dioxide in the respiratory tract

Answer 39

Carbon dioxide is 20X more soluble in blood than O2. → In the blood: -9% transport as CO2 -27% combine with hemoglobin -64% combine with water in plasma to form carbonic acid (H2CO3)

Question 40

What percentage of O2 / CO2 is our inhaled vs exhaled air?

Answer 40

oxygen: 21% inhale, 16% exhale carbon dioxide: 0.04% inhale, 5% exhale

Question 41

How do gases move in the respiratory tract?

Answer 41

Gases move by the process of diffusion (from an area of high pressure to an area of lower pressure).

Question 42

What is the path of air throughout the human body?

Answer 42

nasal passages/mouth → pharynx → trachea → primary & secondary bronchi → bronchioles → alveolar ducts → alveoli → blood → tissue O2 in CO2 out for the entirety of the process*

Question 43

how much lung capacity is used when breathing is at rest?

Answer 43

one-tenth of total lung capacity is used

Question 44

What is tidal volume (TV) when referring to lung volumes?

Answer 44

The volume of air breathed in and out without conscious effort

Question 45

What is inspiratory reserve volume (IRV) volume when referring to lung volumes?

Answer 45

The additional volume of air that can be inhaled with maximum effort after a normal inspiration

Question 46

What is expiratory reserve volume (ERV) when referring to lung volumes?

Answer 46

The additional volume of air that can be forcibly exhaled after normal exhalation

Question 47

What is vital capacity (VC) volume when referring to lung volumes?

Answer 47

The total volume of air that can be exhaled after a maximum inhalation: VC = TV + IRV + ERV

Question 48

What is residual volume (RV) when referring to lung volumes?

Answer 48

The volume of air remaining in the lungs after maximum exhalation (the lungs can never be completely emptied)

Question 49

How do you calculate total lung capacity when referring to lung volumes?

Answer 49

VC + RV = TLC

Question 50

What is VO2 when referring to oxygen usage?

Answer 50

rate at which oxygen is used in the body, measured in millilitres per kilogram per minute

Question 51

What is VO2max when referring to oxygen usage?

Answer 51

is the maximum rate at which oxygen can be used in an individual, measured in millilitres per kilogram per minute

Question 52

What does the circulatory system ensure?

Answer 52

A circulatory system ensures that oxygen and nutrients are delivered to every cell and it allows waste products, that are removed from cells, to be released into the external environment.

Question 53

What are the three fundamental features of the circulatory system?

Answer 53

-a fluid that transports (circulates) materials through the body -a network of tubes in which the fluid circulates -a pump that pushes the fluid through the tubes

Question 54

Most invertebrates have what type of circulatory system?

Answer 54

Most invertebrates, such as snails, insects, and crustaceans, have an open circulatory system where the circulating fluid (blood and tissue fluid) is pumped into an interconnected system of body cavities (or sinuses), where it bathes the cells directly.

Question 55

All vertebrates and some invertebrates have what type of circulatory system?

Answer 55

All vertebrates, as well as some invertebrates such as earthworms, squids, and octopuses, have closed circulatory systems.

Question 56

What is present in a closed circulatory system?

Answer 56

In a closed circulatory system, the fluid (often blood) is contained within a network of tubes, or blood vessels. This system separates blood from the tissue fluid by keeping the blood enclosed in the vessels. The tissue fluid surrounds the cells and provides a medium for the diffusion of substances from the bloodstream to the cells.

Question 57

What type of circulatory system do humans have?

Answer 57

Humans have a closed circulatory system where the blood is pumped through the body by the action of a four-chambered muscular heart.

Question 58

What are the three types of human circulation?

Answer 58

Systemic Circulation: -the flow of blood from the heart to the body tissues and back to the heart -gases, wastes and nutrients are exchanged with body tissues Pulmonary Circulation: -the flow of blood from the heart to the lungs and back to the heart again -the blood exchanges carbon dioxide for oxygen in the lung Cardiac Circulation: -the flow of blood through the heart muscle tissue via the coronary arteries -gases, wastes and nutrients are exchanged with the heart tissue

Question 59

What is the path of blood/circulation throughout the heart?

Answer 59

-blood from your head and arms travels from the superior vena cava into the right atrium -blood from the lower body travels from the inferior vena cava into the right atrium -the right atrium contracts, along with the pull of gravity, forcing the blood into the right ventricle where it is then pumped through the pulmonary arteries to the lungs -oxygen then diffuses into the blood (carbon dioxide out) and then the oxygenated blood goes through the pulmonary veins into the left atrium -the left atrium contracts and forces the blood into the left ventricle -the left ventricle contracts and forces the blood out through the aorta (the largest blood vessel in the body) -the aorta branches into major arteries that carry blood around the body -as the blood passes through the capillary networks in the body tissues, oxygen diffuses out of the blood into the cells -the now deoxygenated blood enters the venules which merge to form veins, and then the veins merge to form larger veins -the largest veins, the inferior vena cava and the superior vena cava enter the right atrium of the heart

Question 60

What are the four valves that ensure that blood only flows in one direction?

Answer 60

semilunar valves: these two valves are located where the ventricles meet the pulmonary arteries and the aorta; shaped like half-moons; prevent back flow into the ventricles when the ventricles relax atrioventricular valves: these two valves are located between the atria and the ventricles; the left valve has two flaps sometimes called the bicuspid valve; the right valve has three flaps - sometimes called the tricuspid valve; prevent back flow of blood from the ventricles into the atria -because the atrioventricular valves are subjected to higher pressures than the semilunar valves, they are supported by tough cords known as chordae tendineae, which are attached to papillary muscles on the inside of the ventricles

Question 61

Does the amount of blood inside an individual depend on the size of them?

Answer 61

yes

Question 62

What is the approximate amount of blood in the human body?

Answer 62

4L - 5L

Question 63

What are some of the functions of blood?

Answer 63

-supplies oxygen to cells -supplies nutrients to cells -equalizes body temperature -transports hormones -transports antibodies -clotting at the site of wounds -removal of carbon dioxide, ammonia and other waste products

Question 64

Blood is a connective tissue

Answer 64

True

Question 65

What is a connective tissue?

Answer 65

a tissue that consists of cells suspended in an intercellular matrix

Question 66

What are the two components of human blood?

Answer 66

-cellular component: red blood cells, white blood cells, platelets -intercellular matrix: yellow-coloured liquid called plasma

Question 67

What is the other name for red blood cells?

Answer 67

erythrocytes

Question 68

What are the functions of red blood cells/erythrocytes?

Answer 68

FOR TRANSPORT -biconcave disks - concave on both sides for greater surface area -transport oxygen from the lungs to the body cells and carry carbon dioxide from the body cells back to the lungs to be expelled -contain hemoglobin (a protein containing iron), to which oxygen attaches -oxygen binding with the iron gives blood its red colour -once oxygen is given up to the cells, the hemoglobin molecule reflects blue light -formed from stem cells in the marrow of the vertebrae, ribs, breastbone, skull, and bones of the arms and legs -while the erythrocytes are developing in the marrow they have a nucleus, as they mature and are released into the bloodstream, the nucleus breaks down and disappears (more room for hemoglobin!) -life span of approximately 120 days -die and are removed in the liver and spleen

Question 69

What is the other name for white blood cells?

Answer 69

leukocytes

Question 70

What are the functions of white blood cells/leukocytes?

Answer 70

FOR PROTECTION -formed in the bone marrow -several different types, all of which have nuclei -one of the first lines of defence against harmful bacteria, viruses, and other organisms that cause disease -attracted to the site of an infection or injury -many use phagocytosis: engulfing the bacteria or harmful substance within the cell membrane; once the cell has engulfed its target, enzymes are released and destroy the target and the leukocyte itself; remnants of the leukocyte and whatever it engulfed are left behind as a whitish substance known as pus

Question 71

What are the two categories of leukocytes (white blood cells)?

Answer 71

granular leukocytes: -neutrophils, eosinophils, and basophils -have granules (small particles, or grains) in their cytoplasm that contain different chemicals that attack foreign material and microorganisms that are brought into the cells agranular leukocytes: -lymphocytes and monocytes -specialized to engulf bacteria and other microorganisms or their toxins -some produce antibodies -monocytes, which enlarge to become macrophages, are the largest leukocytes and are excellent scavengers that clean up bacteria, dead cells, and other debris in the bloodstream and tissues

Question 72

What is the function of the platelets?

Answer 72

FOR PROTECTION -small cell fragments produced from stem cells in bone marrow -essential in blood clotting, or coagulation -when a blood vessel is broken, chemicals in the platelets cause them to stick to collagen fibres in the blood vessel wall; as more and more stick to the fibres, a clot is created to seal the hole in the blood vessel wall

Question 73

What is the function of plasma?

Answer 73

-protein-rich liquid in which blood cells and platelets are suspended -over 90% of plasma is water -dissolved or suspended in the plasma are gases, proteins, nutrients, minerals, ions, hormones, antibodies and enzymes

Question 74

What are the blood proteins present in plasma?

Answer 74

blood proteins present: albumins: concentration determines the amount of water entering or leaving the bloodstream by osmosis globulins: transport lipids, cholesterol, some fat-soluble vitamins, and minerals fibrinogen: critical role in blood clotting; converted to long strands of fibrin, forming a mesh that traps more platelets and blood cells

Question 75

What is serum?

Answer 75

fluid that results when the cells, platelets, and fibrinogen have been removed from whole blood

Question 76

What is anemia?

Answer 76

a condition of a low erythrocyte count or a low hemoglobin level, which leads to low oxygen levels

Question 77

How many times does a healthy heartbeat per minute?

Answer 77

75 times per min

Question 78

What is diastole?

Answer 78

the period of relaxation and filling of the heart with blood

Question 79

What is systole?

Answer 79

the period of contraction and emptying of the heart

Question 80

Describe the mechanics behind the heartbeat

Answer 80

-The two sides of your heart beat in unison, despite being two separate pumps -First the two atria contract, followed by the contraction of the two ventricles -The left ventricle operates at a higher pressure than the right -This is because the left ventricle is responsible for pumping blood throughout the entire body -The right ventricle only pumps blood to the lungs and back

Question 81

Describe why our heart makes the familiar lubb-DUBB sound

Answer 81

lubb: the atrioventricular valves close; a double sound because the left valve closes slightly before the right valve DUBB: occurs as the ventricles relax and the semilunar valves snap shut

Question 82

What does a hissing sound indicate as a heartbeat?

Answer 82

A hissing or murmuring sound indicates that valves are not closing properly and blood is leaking backward.

Question 83

Describe the regulation of our hearts rhythm

Answer 83

-The heartbeat is initiated in a cluster of cells in the right atrium called the sinoatrial (SA node -This small mass of nerve and muscle cells generates between 50 and 100 electrical signals per minute in a regular pattern -The SA node acts as a pacemaker, and its signals set the normal rhythm of the heartbeat -The electrical signals first pass over the atria in a wave, causing the muscles to contract -The signals then reach a second mass of cells called the atrioventricular (AV) node, located in the wall of the heart between the right atrium and right ventricle -From the AV node, special conducting fibres, called Purkinje fibres, run down through the septum and throughout the muscle cells of the ventricles

Question 84

How can the heart rate be adjusted?

Answer 84

the sympathetic and parasympathetic nervous systems

Question 85

What are the four blood types?

Answer 85

type A, type B, type AB and type O

Question 86

Is blood type an inherited trait?

Answer 86

yes

Question 87

How are blood types determined?

Answer 87

blood types are determined by the presence (or absence) of different sugars, called markers, on the cell membranes of erythrocytes

Question 88

Why does incompatibility for blood type occur?

Answer 88

incompatibility occurs because the markers act as antigens, which are considered foreign material; when the immune system detects antigens, it produces antibodies that attach to the antigens; this causes the blood cells to clump together, blocking blood vessels and preventing the circulation of blood and delivery of oxygen

Question 89

What is type O blood?

Answer 89

doesn’t have type A or B markers -people with type O can receive only type O blood -because it has no markers, type O blood can be transfused into individuals with any blood type -a person with type O is said to be a universal donor

Question 90

What is type AB blood?

Answer 90

has both protein markers -compatible with any type of donated blood -can only be transfused into another type AB person -a person with type AB is said to be a universal recipient

Question 91

What is type A blood?

Answer 91

has the protein marker A -can be transfused into a person with type A or type AB blood because their blood already has the A marker

Question 92

What is type B blood?

Answer 92

has the protein marker B -can be transfused into a person with type B or type AB blood because their blood already has the B marker

Question 93

Explain the rhesus factor

Answer 93

-another inherited factor -affects the compatibility of blood types -an antigen on erythrocyte membranes that produces an antibody reaction, though not as severe as the antibody reaction to blood type markers -present in 85% of the population: individuals are said to be Rh-positive -15% of the population: the rhesus antigen is not present; individuals are said to be Rh-negative -individuals with Rh-negative blood may donate their blood, but should not receive blood from, individuals with Rh-positive blood

Question 94

Describe the structure of the heart

Answer 94

-located in the middle of the chest, directly under the breastbone -a wall of muscle called the septum separates the heart into two parallel pumps, each with an atrium and a ventricle -the atria (at the top of the heart) receive blood and pump it into the ventricles -the ventricles (at the bottom of the heart) pump blood into two circuits: the pulmonary circuit and the systemic circuit -right side of the heart pumps blood to the pulmonary circuit (the lungs) -the left side of the heart receives the blood from the pulmonary circuit and pumps it out through the systemic circuit (the rest of the body) -ventricular walls are thicker (more muscular) because they have to pump blood over much longer distances and through capillary networks -layers of muscles in the ventricles are arranged spirally around the heart, and when they contract, produce a slight twisting motion that wrings the blood out of the ventricles - the heart is surrounded by the pericardium - a two-layered connective tissue membrane that has fluid between the layers; protects the heart from friction with other tissues and organs in the chest cavity as it beats -the heart has a higher need for oxygen than other muscle tissue (8 times as much!) so it has its own supply of blood vessels, the coronary blood vessels

Question 95

What are the three types of blood vessels?

Answer 95

artery, capillary, vein

Question 96

What do the arteries do as blood vessels?

Answer 96

-has 3 layers; epithelial cells, smooth muscle and connective tissue -can stretch -thick, muscular -carrries blood AWAY from the heart

Question 97

What do the capillaries do as blood vessels?

Answer 97

-thin with a very narrow diameter -one cell thick -abundant -site of gas exchange with tissue cells

Question 98

What do the veins do as blood vessels?

Answer 98

-elastic -wall thinner than artery -has valves -carries blood toward the heart