Lesson 4: Cardiovascular, Respiratory, Lymphatic and Endocrine Systems Flashcards
The cardiovascular, circulatory system is a closed-circuit system composed of?
the heart, blood vessels and blood
Blood continuously travels a circular route, what is this route?
it flows through the heart into the arteries, then to the capillaries into the veins and back round to the heart.
What are arteries?
the blood vessels that deliver oxygen-rich blood from the heart to the tissues of the body.
What are capillaries?
They are very tiny blood vessels that help to connect your arteries and veins in addition to facilitating the exchange of certain elements between your blood and tissues.
They are so small a single red blood cell barely fits through them
What are veins?
blood vessels that carry blood towards the heart.
Veins usually carry deoxygenated blood back to the heart, what 2 veins are the exceptions?
Umbilical and pulmonary that carry oxygenated blood
What is the liquid component of blood called and what does is carry?
Plasma carries hormones, plasma proteins, food materials, ions and gases throughout the body.
What are 4 components of blood?
- plasma
- red blood cells
- white blood cells
- platelets
The primary function of blood is __________.
transportation
Which system plays an important role in temp regulation and acid-base balance?
the cardiovascular system
What do each of the following carry/do: arteries/arterioles, veins/venules and capillaries?
- Arteries - carry oxygen rich blood away from the heart
- Veins return oxygen poor blood to the heart
- Capillaries provide sites for gas, nutrient and waste exchange between the blood and tissues
What is arteriosclerosis?
Hardening of the arteries and narrowing of the arteries due to plaque accumulation
What contributes to arterial rigidity and decreases the arteries’ ability to expand (most common in older adults)?
arteriosclerosis
As arteries lead away from the heart, they branch off into smaller, microscopic vessels called?
arterioles
What do arterioles develop into when carrying blood?
beds of much smaller structures called capillaries
Where do capillaries allow the exchange of materials between?
Between the blood and interstitial fluid between cells
Where does blood pass to after capillaries?
To small venous vessels called venules
As venules lead (blood) back to the heart, what do they develop into?
They increase in size and become veins
Are the walls of veins thinner and less elastic than arterial walls?
yes
What is commonly found inside the veins of lower limbs?
Valves that allow blood to flow only toward the heart
What are the 2 major veins in the body?
inferior and superior vena cava
Where does blood leaving the inferior/superior vena cava veins empty directly into?
It directly empties into the heart where it is transported to the lungs to pick up a fresh supply of oxygen.
Where is the heart located and what does it act as?
It is located between the lungs and lies just left of center, behind the sternum. It acts as a pump that pushes blood throughout the body.
The heart is divided into 4 chambers, what are they each responsible for?
the 2 right chambers are responsible for pulmonary circulation whilst the 2 left chambers are responsible for systemic circulation
The chambers of the heart consist of X2 Atria and X2 ventricles, what is the difference between atria and ventricles?
Atria receive blood returning to the heart from the body and ventricles pump blood from the heart to the body.
What is the muscular wall that separates the right and left sides of the heart? What does it do?
The Interventricular septum prevents the mixing of blood from either side of the heart.
What are the propulsion chambers and receiving chambers of the heart?
Propulsion = ventricles Receiving = atria
How does blood move within the heart?
from the atria to the ventricles and then to the arteries
How is backflow of blood from the arteries into the ventricles prevented?
By the pulmonary semilunar valve and aortic semilunar valve.
What do the left/right atrioventricular valves do?
They connect the atria with the right and left ventricles respectively and prevent backward movement of blood.
How does the pulmonary circuit work?
It transports deoxygenated and CO2 elevated blood to the right side of the heart where it is pushed to the lungs to absorb oxygen and release carbon dioxide.
The oxygenated blood then flows back to the heart.
How does the systemic circuit work?
It transports newly oxygenated blood from the lungs to the left side of the heart and pumps it to various tissues of the body.
Where does all blood from the venous system first enter?
right atrium
What is the journey of venous blood?
It flows first to the right atrium, enters the right ventricle which pumps it through the pulmonary arteries to the lungs to be reoxygenated and relieved of CO2. It then flows through the pulmonary veins to the left atrium, through the left ventricle and then pumped via the aorta to the rest of the body.
What is the cardiac cycle?
The period from the beginning of one heartbeat to the beginning of the next
True or false, the right and left sides of the heart perform their pumping actions simultaneously?
True
When the heart beats, do both atria contract together to empty blood into the ventricles?
yes
When both atria contract, what circuits is the blood delivered to?
the pulmonary and systemic circuits
What does systole and diastole refer to?
These are the repeating phases of contraction and relaxation of the heart.
Systole is the contraction phase of the cardiac cycle in which blood leaves the ventricles.
Diastole is the relaxation phase in which blood fills the ventricles.
The respiratory system makes it possible for the body to?
- exchange gases between the external environment and tissues
- replace oxygen and remove CO2 from the blood
- vocalization
- regulate acid-base balance during exercise
What is the respiratory system made up of? (7)
nose nasal cavity pharynx larynx trachea bronchi lungs
Where does gas exchange occur in the lungs?
Within microscopic air sacs called alveoli
How much air do humans approx breath per minute through the nose at rest vs the mouth during exercise?
5-6 litres vs 20-30 litres per minute
What is the journey of air entering the respiratory system?
- Warmed and passes through the pharynx and larynx
- Travels through trachea to right and left primary bronchi
- The primary bronchi divide into secondary bronchi which divides into tertiary bronchi that results into bronchioles
- The bronchioles further divide into alveoli where gas exchange occurs
Where does the trachea (windpipe) extend to?
5th and 6th thoracic vertebrae where it divides into 2 smaller branches: right and left bronchi
How many alveoli do the lungs contain?
approx 300 million
What is the estimated surface area available for diffusion in the human lung?
approx the size of a tennis court
What are the lungs encased and separated by?
They are encased within the rib cage and separated by the mediastinum
The mediastinum separates the two lungs but what does it contain?
heart, aorta, esophagus and part of the trachea
What is the most important muscle of inspiration and the only skeletal muscle considered essential for life?
the diaphragm
What happens when the diaphragm contracts?
It forces the abdominal contents downwards and forwards whilst the external intercostals lift the ribs outwards.
This reduces pressure surrounding the lungs and causes them to expand which allows airflow into the lungs.
What are the external intercostals?
a group of muscles that run between the ribs
At rest, the diaphragm and external intercostals perform most of the inspiration work - what accessory muscles are recruited during exercise? How do they help?
pectoralis minor
scalenes
sternocleidomastoid
They assist the diaphragm and external intercostals to further increase the volume of the thorax and aid in inspiration