Anatomy Unit 5 : intro, heart, fetal circulation, respiratory system

Thoracic cavity

contains heart and lungs

Pleural cavities (of thoracic cavity)

surround lungs

Mediastinum (of thoracic cavity)

contains heart, esophagus, trachea, blood vessels, etc

Pericardial cavity (within mediastinum)

surrounding the heart

Abdominopelvic cavity

Abdominal (of abdominopelvic) cavity

gastrointestinal structures

Pelvic (of abdominopelvic) cavity

urinary bladder, reproductive organs, last part of digestive tract

The Thoracic and Abdominopelvic cavity are separated by

the diaphragm

Diaphragm

Large, flat muscle at the bottom of the chest cavity that helps with breathing

Serous membrane

lines the viscera (organs) and the walls of the ventral body cavity

Parietal layer of serous membrane

lines cavity walls

Visceral layer of serous membrane

adheres to surface of organ

Serous membrane produces...

serous fluid

Serous fluid function

reduce friction between organs and walls

Serous fluids are named for

the cavity that it's in

Parietal/visceral pericardium

pericardial cavity and heart surface

Parietal/visceral peritoneum

abdominopelvic cavity and viscera inside it

Parietal/visceral pleura

pleural cavity and lung surface

2 divisions of nervous system

CNS (brain and spinal cord)

PNS (divided into 2 parts)

2 divisions of PNS

Somatic (sensory/afferent) and Autonomic (motor/efferent)

Somatic nervous system

voluntary/things we control

motor: skeletal system

sensory: touch, temperature, pain (outside world)

Somatic: efferent pathway

one neuron system (1 motor neuron travels out to a muscle to tell it to contract)

Somatic: neurotransmitter & response of target organ

acetylcholine (excitatory)

Autonomic nervous system

involuntary

motor: smooth muscle (digestive tract)

cardiac muscle

glands

sensory: organs (inside world)

Autonomic: efferent pathway

two neuron system: presynaptic and postsynaptic

(neuron travels out and synapses with another neuron --> where they meet is called a ganglion)

Autonomic: neurotransmitter & response of target organ

Presynaptic: acetylcholine (excitatory)

Postsynaptic: varies between sympathetic (norepinephrine and epinephrine) & parasympathetic (acetylcholine) --> excitatory or inhibitory

2 divisions of Autonomic nervous system

parasympathetic (rest & digest --> slows things down)

sympathetic (fight or flight --> speeds things up)

Parasympathetic

routine maintenance "rest & digest" ; inhibits/slows down body functions (except digestion)

Parasympathetic only innervates

internal organs

Parasympathetic location/origin

in the brainstem (CN 3, 7, 9, 10)

sacral region (S2-S4)

Parasympathetic fiber length

Presynaptic: long

Postsynaptic: short

Parasympathetic location of ganglia

In/near visceral effector organs (terminal ganglia) -->

named ganglia in the head

intramural ganglia in the thorax and abdomen (within the wall of the effector organ)

Parasympathetic (Cranial Outflow): Presynaptic fibers run via

Oculomotor n. (CN III) smooth muscle in the eye

Facial n. (CN VII)

lacrimal, submandibular, sublingual glands

Glossopharyngeal n. (CN IX)

parotid gland

Vagus n. (CN X)

organs in thorax & GI tract through 2/3 of transverse colon

Parasympathetic (Sacral Outflow): Presynaptic neurons travel...

through ventral root --> spinal n. --> ventral rami

exit ventral rami as pelvic splanchnic nn.

Pelvic splanchnic nn. innervate 1/3 of large intestine & its components

Sympathetic

mobilization & increased metabolism; "fight, flight, or fright"; speeds up or stimulates body functions (except digestion)

Sympathetic location/origin

thoracolumbar region (T1-L2)

lateral horn (where cell bodies are)

Sympathetic fiber length

Presynaptic: short

Postsynaptic: long

Sympathetic location of ganglia

close to spinal cord;

Paravertebral ganglia: sympathetic chain (located on both sides of vertebral column; extend from cranial base to coccyx)

Prevertebral ganglia:

on abdominal aorta (celiac ganglion; superior mesenteric ganglion; inferior mesenteric ganglion)

Sympathetic Outflow (3 options)

1. synapse at paravertebral ganglia at same level

2. synapse at paravertebral ganglia at a different level

3. does not synapse on chain --> splanchnic nerve (will synapse at a prevertebral ganglia on abdominal aorta)

Adrenal medulla

modified sympathetic ganglion; a gland sitting above kidney; produces neuro-horomones that travel through the whole body (sends signal into blood stream)

Parasympathetic vs sympathetic effects on organs

Cardiovascular system major components

heart, blood vessels, blood

Cardiovascular system major function

transportation of nutrients and oxygen, waste products, and hormones

The heart is located ...

encased in pericardial sac in the middle mediastinum; apex of the heart points down towards our left hip

2 circuits of blood from the heart

Pulmonary & Systemic circuits

Pulmonary circuit path

Right side of heart pumps (unoxygenated) blood to lungs, then it goes back (oxygenated) to left side of heart

"Pulmonary"

heart and lungs

Why does blood travel to the lungs

to become oxygenated

Systemic circuit path

Left side of heart pumps (oxygenated) blood to the body, then it goes back to right side of heart (deoxygenated)

Right side circulation

Deoxygenated blood FROM body enters right side of heart & gets pumped TO lungs

Left side circulation

Oxygenated blood FROM lungs enters left side of heart & gets pumped TO body

Right atrium

Receives deoxygenated blood from the body

Right ventricle

pumps deoxygenated blood received from right atrium to the lungs

Left atrium

receives oxygenated blood from the lungs

Left ventricle

received oxygenated blood from left atrium and pumps it to the body

Veins

take blood towards the heart

Arteries

take blood away from the heart

Right auricle

increases holding capacity of right atrium

Left auricle

Great vessels of the heart

veins: superior vena cava

inferior vena cava

pulmonary veins

arteries: pulmonary trunk and arteries

aorta

Superior vena cava

sits superiorly to right atrium; returns blood from thoracic wall, upper limb, head, and neck

What drains into the superior vena cava

right and left brachiocephalic veins

Inferior vena cava

sits inferiorly to right atrium; returns blood from the abdomen, pelvis, and lower limb

What drains into the inferior vena cava

right and left common iliac veins

Pulmonary veins

Pulmonary trunk

Pulmonary arteries

branches of pulmonary trunk

Aorta

Right atrium receives deoxygenated blood from

superior vena cava, inferior vena cava, coronary sinus

Coronary sinus

drains deoxygenated blood from the heart into the right atrium

Right ventricle discharges deoxygenated blood into the pulmonary circuit via the

pulmonary trunk (splits into pulmonary arteries)

Left atrium receives oxygenated blood from

4 pulmonary veins; 2 right veins and 2 left veins

Left ventricle discharges oxygenated blood into the systemic circuit via the

aorta: ascending aorta, arch of aorta, descending aorta

Oxygenated blood travels in

both arteries and veins

What prevents backflow in chambers/keeps blood going in one direction?

valves

Valves of the heart

4 total:

2 atrioventricular

2 semilunar

Atrioventricular valves function

prevent backflow into atria

Atrioventricular valves

Tricuspid & Bicuspid/Mitral valves

"Try before you Buy"

Tricuspid valve

right side; between right atrium and rightt ventricle

Bicuspid or Mitral valve

left side; between left atrium and left ventricle

Chordae tendineae

attached to papillary muscles; act as anchor points (holding heart together)

Semilunar valves function

prevent backflow into ventricles

Semilunar valves

Pulmonary Semilunar & Aortic Semilunar

Pulmonary Semilunar valve

between right ventricle and pulmonary trunk

Aortic Semilunar valve

between left ventricle and aorta

Systole

ventricles contract to pump blood out of the heart

During systole tricuspid & bicuspid valves _________

close (don't want back-flow)

"lub" sound

Diastole

ventricles relax so blood can fill them again

During diastole tricuspid & bicuspid valves ________ and the pulmonary and aortic semilunar valves _________

open ; close (don't want back-flow from outflow vessels)

"dub" sound

Flow of blood through heart

Layers of the heart

epicardium (superficial)

myocardium endocardium (deep)

Pectinate muscle

reduces stress within right atrium

Opening of coronary sinus

within right atrium; drains deoxygenated blood

Fossa ovalis

within right atrium; opening in utero that closed after birth

Trabeculae carneae

papillary muscles attach here; muscle that makes up wall between right and left ventricle

Maximal blood flow to the myocardium occurs when the heart is __________

diastole (relaxed)

There is little blood flow through the coronary circulation when the heart is ____________

systole (contracting)

Contraction of myocardium compresses __________

coronary arteries

Entrances into the coronary circulation are partially blocked by the ____________

cusps of the open aortic semilunar valve

Right coronary artery

exits from aorta and travels between right atrium and right ventricle