Biology Unit 2

Single loop system

blood is oxygenated at gill capillaries then goes to body tissues. Then blood returns to the two chambered heart to be pumped again to the gills.

Double loop system

Blood becomes oxygenated at the pulmonary loop (lungs) , then is returned to the heart. It is then pumped to the systemic loop to deliver oxygen to body tissues and pick up carbon dioxide waste from cellular respiration.

What is the advantage of a double loop system

there is a constant supply ox oxygenated blood to the tissues of the body (which need oxygen for cell respiration)

Diastole

when atria and ventricles are at rest

when heart is at rest which vales are open, allowing blood to fill atria and ventricles

Atrioventricular valves

Why is atrial contraction before ventricle contraction be an efficient way

maximizes blood in the ventricles

As the atria contract what happens to pressure inside it?

It increases because the volume decreases

As the ventricles start to contract, the AV valves close — why is this important?

It prevents the backflow of blood

where will blood go when SL valves open

to the pulmonary or systemic loops of the circulatory system

Characteristics of Arteries

away from the heart, narrow Lumen, high blood pressure, thick walls, built for withstanding and maintaining high pressure

Characteristics of veins

toward the heart, wide lumen, lowest pressure of blood, thin walls, built to maximize blood flow in one direction at low pressure against gravity

Capillaries

low pressure, thinnest, built for exchange of materials

Muscles around the veins _____ to help return blood to the heart to open or close _____

squeeze, valves

why do capillaries have one layer of cells

helps gas exchange occur more efficiently

blood moves slowest at capiilaries why?

more time for gas and nutrient exchange between blood and body tissues

what are 3 molecules found in the tissue fluid?

glucose, oxygen, co2

What do lymphatic capillaries do?

place where excess tissue fluid goes

What happens @ capillaries

they connect oxygenated and deoxygenated blood. Oxygenated blood gets deoxygenated

systolic pressure

pressure in arteries when ventricles contract normal = 120 mmHg

Diastolic Pressure

pressure in arteries when ventricles relax Normal = 80 mm Hg

What is Atherosclerosis

when cholesterol accumulates in artery creating plaque, restricting blood flow and if it bursts it makes a blood clot.

CHD

when disease influences structure of heart function. Most common is coronary artery disease when plaque restricts blood flow to heart tissue.

Myocardial infarction

when blockage in artery severely restricts blood flow, can make tissue death.

Factors that increase occlusion

Trans-unsaturated fats, stress, smoking, high LDL

Consequences from occlusion

heart pain, heart attack

SA node

in right atrium makes pace of heart beat

How does it maintain heart BEAT

first it excites the atriums then the impulse goes to the ventricles

where is the AV node

middle of all four chambers

EKG

records the electrical signals from the heart through a series of electrodes.

Why does QRS wave have a larger amplitude

ventricular contraction (QRS) needs more of an impulse than atrial contraction (P-wave)

How do pace makers help

deliver regular impulses or only send impulses when it detects one has been missed.

Baroreceptors

specialized proteins associated with sensory neurons. Located in the aortic arch and carotid arteries. Monitor blood pressure.

Medullah

increases heart rate and stroke volume when blood pressure increases.

Chemoreceptors

monitor co2, ph, and oxygen levels

Alveoli

the “drop off” point for carbon dioxide

Alveoli adaptations

one layer of cells, gases have short distance to travel, lots of surface area, slow movement for more gas exchange

When we inhale concentration is higher in alveoli, this makes oxygen move from high to low

How do RBC help transport oxygen

rbc have protein hemoglobin. Each hemoglobin carries 4 molecules of oxygen. Allows oxygen to go through blood stream

How does Hemoglobin “pick up” Oxygen?

A hemoglobin molecule holding an oxygen molecule is more likely to pick up more oxygen because its shape changes.

When CO2 binds hemoglobin binds to O2 less. What areas have high co2

tissues doing cellular respiration

What’s the benefit of releasing O2 where CO2 is high?

hemoglobin releases O2 in tissue where it can be used

A hemoglobin molecule holding an oxygen molecule is more likely to pick up more oxygen.

Fetal hemoglobin has a higher affinity for oxygen molecules than adult hemoglobin.

In inhalation…

diagram is flat, contracts, ribs go up and outwards, pressure decreases

Exhalation…

dome shaped, rib muscles relax, rib cage goes down and inwards, volume decreases, pressure increases

antagonistic pairs

muscles that influence each other’s elongation

control of ventilation

Chemoreceptors in the medulla of the brain detect when the blood pH falls below 7.35. When the lower pH is detected, the medulla sends signals via nerves to the diaphragm and intercostal muscles to increase the rate of ventilation.

tidal volume

volume of air breathed without conscious effort

Inspiratory Reserve Volume

additional volume that can inhaled after a normal breath

Expiratory reserve volume

additional volume that can exhaled after a normal breath

vital capacity

all three added, total volume of air after max inhalation