Thorax and Abdomen
Abdomen
Abdominal Viscera
Esophagus
Functions
Prevent food and liquids from entering the windpipe or nasal cavity
Transport food and liquids from the mouth to the stomach
Vomiting, eructation, and the gag reflex
Structure
Mucosa (inner lining)
Submucosa (connective tissue layer)
Muscularis propria (muscle layer with inner circular and outer longitudinal fibers)
Adventitia (outer connective tissue layer)
Neuro Vasculature
Innervated by the sympathetic and parasympathetic divisions of the autonomic nervous system
The vagus nerve is the primary motor nerve of the esophagus
Passes through the thoracic cavity and into the abdomen
Stomach
Function
Churns the food to help break it down mechanically and chemically
Nerves
Sympathetic
Cardiac plexus
influences gastric function by regulating motility and acid secretion in the stomach
Greater splanchnic nerve
T6-T9
Parasympathetic
Vessels
Venous
L & R gastric veins
Drain into portal vein
Short gastric
Drain into splenic vain
Arterial
Celiac Trunk
Gastric
Right
supplies blood to the lesser curvature of the stomach
Posterior
Supplies blood to the superior and posterior regions of the stomach, near the border of the cardia and fundus
Short
supply blood to the fundus and proximal body of the stomach, including the cardiac orifice
Left
supplies the lower esophagus and part of the stomach
Anatomy
Sections
Pyloric
Body
Fundus
Cardia
Curvatures
Greater
Lesser
Small Intestine
Functions
break down food, absorb nutrients the body needs, and excrete unnecessary components
Sections
Duodenum
Superior
L1
Descending
L1-L3
Major duodenal papilla
allows bile and pancreatic enzymes to flow into the duodenum
Ampulla of Vater
Where the pancreatic and bile ducts meet to release digestive juices into the small intestine
Inferior
L3
Ascending
L2-L3
Ligament of Treitz
anchors the duodenum
Jejunum
Structure
circular folds in its submucosa called plicae circulares
Attached to a long mesentery, allowing for mobility within the abdominal cavity
LUQ
Ileum
Structure
has a mucosa (inner lining), submucosa, muscularis externa (muscle layer), and serosa (outer layer)
contains finger-like projections called villi that increase the surface area for nutrient absorption
receives blood supply from the superior mesenteric artery
RLQ
Nerves
Meissner's plexus
parasympathetic input
Auerbach's myenteric plexus
sympathetic and parasympathetic
Vessels
Arterial
Superior mesenteric artery (SMA)
supplies oxygenated blood
Venous
Superior mesenteric vein (SMV)
Drains blood from the small intestine
Large Intestine
Function
absorbing water and electrolytes
producing and absorbing vitamins
forming and propelling feces toward the rectum
Colon
Ascending
Right side of the abdomen
runs superiorly on the right side of the abdomen from the right iliac fossa to the right lobe of the liver
Descending
left side of the body, between the transverse colon and sigmoid colon
Transverse
Between the right and left colic flexures, usually at the level of the 10th rib
Sigmoid
Stores fecal matter until it's ready to leave the body
Usually in the pelvis, but can become displaced into the abdominal cavity
Appendix
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attached to the large intestine
Rectum
responsible for storing feces and then moving it toward your anus
Vessels
inferior mesenteric artery (IMA)
Veins
Superior mesenteric vein
Drains the ascending colon, transverse colon, and ileocolic vein
Inferior mesenteric vein
Drains the descending colon and sigmoid colon
Nerves
Vagus
regulates tone and volume in the large intestine
Pelvic
controls the lower part of the GI tract, including the rectum and anus
Features
Haustra
slow down the movement of digested food through the colon
Teniae Coli
Run the length of the ascending, transverse, descending, and sigmoid colons
Shorten the colon wall to create haustra
Omental Appendices
made of fat and the peritoneum, a serous tissue that lines the abdominal wall and covers most abdominal organs
Cecum
connects the small intestine to the colon
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Liver
Function
filters all of the blood in the body and breaks down poisonous substances, such as alcohol and drugs
Anatomy
Diaphragmatic
fits under the vault of the diaphragm which in front separates it on the right from the sixth to the tenth ribs and their cartilages, and on the left from the seventh and eighth costal
Visceral
posteroinferior surface that faces the abdominal organs and other adjacent structures
Lobes
Right
The largest lobe of the liver
Left
Smaller than the right lobe
Quadrate
Located on the inferior surface of the right lobe
Caudate
between the left and right lobes, and in an anterior and superior position
Vessels
Right hepatic vein
Located between the right anterior and right posterior sectors
Middle hepatic vein
Located between the right anterior sector and segment IV
Left hepatic vein
Located between the left medial and left lateral sectors
Hepatic portal vein
a vein conveying blood to the liver from the spleen, stomach, pancreas, and intestines.
Nerves
Sympathetic nerves
Originate in the celiac and superior mesenteric ganglia, which receive pre-ganglionic neurons from the spinal cord.
Parasympathetic nerves:
Originate in the dorsal motor nucleus of the vagus nerve in the brainstem.
Gall Bladder
Function
Stores bile
Location
RUQ
gastrointestinal organ located within the right hypochondrial region of the abdomen.
Spleen
Function
Stores and filters blood
Location
located in the upper left quadrant of the abdomen, behind the stomach and under the left ribs
Vessels
Splenic vein
carries blood from the spleen, pancreas, and part of the stomach to the liver
Splenic artery
supplies oxygenated blood to the spleen, stomach, and pancreas:
Nerves
Sympathetic
The celiac plexus provides sympathetic innervation to the spleen.
Parasympathetic
The vagus nerve (CN X) provides parasympathetic innervation to the spleen.
Pancreas
Function
Exocrine
secretion of digestive enzymes, ions and water into the duodenum
Endocrine
produce and release hormones that regulate blood sugar levels:
Parts
Head
Neck
Body
Tail
Ducts
Main pancreatic
drains pancreatic fluid from the pancreas, which contains digestive enzymes and fluids that help break down food.
Accessory pancreatic
secondary drainage system for the main pancreatic duct, which can help reduce pressure and prevent acute pancreatitis.
Vessels
Greater pancreatic artery
The largest blood vessel that supplies oxygenated blood to the pancreas. It originates from the splenic artery.
Dorsal pancreatic artery
A branch of the splenic artery that supplies the pancreas. It runs along the posterior margin of the pancreas and divides into left and right branches.
Transverse pancreatic artery
Also known as the inferior pancreatic artery, it supplies the pancreatic tail and body. It originates from the proximal splenic artery.
superior mesenteric
A major blood vessel in the digestive system that supplies oxygenated blood to the pancreas and the lower parts of the intestine.
gastroduodenal
A small vessel that supplies blood to the head of the pancreas, the pylorus, and the proximal part of the duodenum.
Nerves
The pancreas receives involuntary innervation via the autonomic nervous system (ANS). Its parasympathetic innervation originates from the vagus nerve (CN X)
sympathetic innervation from the greater and lesser splanchnic nerves (T5-T12).
Kidney
Function
remove waste products from the blood and produce urine. control blood pressure.
Parts
Renal hilum
Renal pelvis
Renal pyramids
Major Calyces
Minor Calyces
Vessels
Renal arteries
supply oxygenated blood to the kidneys, adrenal glands, and ureters
Renal veins
carry filtered blood from the kidneys to the heart:
Nerves
Efferent
regulate renal function, including sodium reabsorption, glomerular filtration, and renin release.
These nerves are sympathetic and originate from the neuraxis.
Afferent
These nerves travel from the kidney to the dorsal root ganglia along the spinal cord. The least splanchnic nerve is the primary afferent signaling nerve from the kidney to the brain.
Glands
Produce hormones that control many important body functions, including blood pressure, blood sugar, metabolism, and the body's response to stress
Posterior Abdominal Wall
Fasica
Psoas
The psoas fascia is a thick layer of connective tissue that covers the psoas major muscle in the posterior abdominal wall:
Thoracolumbar
The TLF has three layers: anterior, middle, and posterior. The posterior layer extends from the neck to the loin, while the anterior and middle layers are limited to the lumbar region.
The TLF spans the length of the back, from the neck to the sacrum. It's most developed in the lumbar region.
Nerves
The nerves of the posterior abdominal wall primarily originate from the lumbar plexus
L1-L4 spinal nerves and sometimes includes T12
Muscles
Psoas major
T12–L5.
Hip flexion and external rotation
Iliacus
flexes and rotates the thigh bone
femoral nerve (L2–L4).
Quadratus lumborum
extensor of the lumbar spine, a stabilizer of the lumbar area, capable of pelvic tilting laterally and capable of acting as an inspiratory accessory muscle.
The quadratus lumborum (QL) muscle is innervated by the subcostal nerve (T12) and the first three nerves of the lumbar plexus (L1-L3):
Vessels
Abdominal aorta
The abdominal aorta is a large blood vessel that runs along the posterior abdominal wall, supplying blood to the abdomen and other parts of the body:
T12
Veins
Inferior vena cava
A large vein that receives venous drainage from all structures below the diaphragm. It's located on the posterior abdominal wall, to the right of the abdominal aorta and in front of the vertebral column.
Lymphatics
super
Follow the superficial circumflex blood vessels in the lumbar and iliac regions
deep
Lumbar
Follows the lumbar arteries and drains into the lateral aortic nodes
Iliac
Follows the deep circumflex iliac artery and drains into the external iliac nodes
Anterio-lateral Abdominal Wall
Fascia
Camper
Protects the abdominal organs, insulates to maintain a constant temperature, and separates the skin from the muscles
Extends from the xiphoid process to the inguinal ligaments, and past the pubic symphysis
Intermediate
Thoracolumbar
Located on either side of the lumbar vertebrae, the TLF is most prominent in the upper lumbar region.
The TLF supports the lower back, helps maintain spinal alignment, and protects the underlying muscles and spinal structures. It also contains nerve endings that help with proprioception, the body's ability to sense its position and movement.
Abdominal
attaches, stabilizes, encloses, and separates muscles and other internal organs.
Scarpa
Scarpa's fascia is a thin membrane of connective tissue located in the lower abdomen and anterior abdominal wall:
allow for smooth movement, protect the underlying organs, provide structural support to the abdominal wall, role in maintaining fluid balance and tissue pressure in the region.
Muscles
External oblique
The external oblique is one of the outermost abdominal muscles, located on the sides of the abdomen, and sits on top of the internal obliques.
The external oblique's primary function is to rotate the trunk from side to side. It also helps stabilize the core, move the spine, and assist with breathing.
Internal oblique
The internal obliques are located on the sides of the trunk, just inside the hip bones, and on top of the external obliques.
The internal obliques work with the external obliques to help the trunk twist and turn. They also help with exhaling and stabilizing the spine.
Transversus abdominus
located between the ribs and pelvis, and wrapping around the trunk from front to back.
postural support and help contain and support the organs inside the trunk. It's also a main core muscle that supports the lumbopelvic region.
Rectus abdominis
move the body between the ribcage and the pelvis.
Flexion of the spine
Pyramidalis
Found at the base of the pubic bone, within the rectus sheath, anterior to the rectus abdominis muscle.
Function: Considered to have a minor role in stabilizing the abdominal wall by tensing the linea alba
Rectus shealth
fibrous compartment in the abdomen that contains the rectus abdominis and pyramidalis muscles
Transverse section
Above umbilicus
Rectus sheath splits around the rectus
Below umbilicus
Rectus sheath anterior to rectus
Internal surface
Peritoneal folds
Median umbilical
Lateral umbilical
Peritoneal fossae
Lateral inguinal
medial inguinal
supravesical
Neruovasculature
Nerves
Thoracoabdominal
T7-T12
Lateral cutaneous
T7-T9
Iliohypogastric
L1
Ilioinguinal
L1
Vessels
Internal Thoracic
musculophrenic
The musculophrenic artery is a branch of the internal thoracic artery that supplies the pericardium and abdominal wall:
superior epigastric
The superior epigastric artery supplies blood to the upper central abdominal wall and skin, and the upper rectus abdominis muscle:
Aorta
posterior epigastric
Supplies blood to the upper part of the rectus abdominis muscle and the linea semilunaris
subcostal
The subcostal arteries supply the muscles and skin beneath the 12th rib of the anterolateral abdominal wall
External iliac
inferior epigastric
The inferior epigastric artery supplies oxygen-rich blood to the abdominal wall, including the skin, muscles, and parts of the male reproductive system
deep circumflex iliac
The deep circumflex iliac artery (DCIA) supplies blood to the muscles, skin, and bone of the lower abdomen and pelvis
femoral artery
superficial epigastric
The superficial epigastric artery's main function is to supply blood to the skin and superficial inguinal lymph nodes of the anterior abdominal wall
superficial circumflex
supplies blood to the skin, subcutaneous tissue, and superficial inguinal lymph nodes of the abdominal wall and groin
Spermatic cord
Layers
Internal spermatic fascia
External spermatic fascia
Parts
Ductus deferens
Carries sperm from the epididymis to the urethra
Runs through the spermatic cord, inguinal canal, and pelvic cavity, looping over the bladder and ending at the ejaculatory duct
Arteries
cremasteric
A branch of the inferior epigastric artery, this artery supplies blood to the skin of the scrotum, including the cremaster muscle, and the layers of the spermatic cord.
testicular
Also known as the internal spermatic artery, this artery branches from the abdominal aorta and supplies blood to the testis, epididymis, and spermatic cord.
Plexus
web-like network of veins in the spermatic cord that surrounds the testicular artery. It begins in the scrotum and extends into the inguinal canal.
Helps regulate temperature
Cremaster muscle
raise and lower the testes in order to regulate scrotal temperature for optimal spermatogenesis and survival of the resultant spermatozoa.
Lymphatic vessels
The lymphatic vessels of the scrotum drain into the superficial inguinal lymph nodes.
Fight infection
Inuinal region
Inguinal ligament
The inguinal ligament is a band of tissue that runs from the pubic tubercle to the anterior superior iliac spine (ASIS) in the lower abdomen.
It's also known as Poupart's ligament or groin ligament
Iliopubic tract
The iliopubic tract is a band of tissue that runs from the iliopectineal arch to the pubic bone
Inguinal canal
Deep ring
It is an opening in the transversalis fascia, forming the deep boundary of the inguinal canal.
serve as the entrance point of the inguinal canal, allowing the passage of the spermatic cord in males and the round ligament of the uterus in females
superficial ring
Location: Located above the pubic tubercle, just superior to the crest of the pubis
The exit point for the inguinal canal, which allows passage for the spermatic cord in males, the round ligament in females, blood vessels, lymphatics, and the ilioinguinal nerve
walls
Floor
Iliopubic tract
Inguinal ligament
lancunar ligament
Anterior
composed of the aponeurosis of the external oblique muscle and reinforced laterally by the internal oblique muscle.
Posterior
formed by the transversalis fascia, conjoint tendon, and deep inguinal ring.
Roof
formed by the medial crus of the aponeurosis of the external oblique, the musculoaponeurotic arches of the internal oblique and transverse abdominal muscles, and the transversalis fascia.
Diaphragm
Vessels
Superior phrenic arteries: Arise from the thoracic aorta
Musculophrenic artery: A branch of the internal thoracic artery
Pericardiacophrenic artery: A branch of the internal thoracic artery
Inferior phrenic arteries: Often arise from the anterior trunk of the aorta above the celiac artery
Lower internal intercostal arteries: Supply blood to the diaphragm
Nerve
Phrenic nerve
C3 through C5
Functions
Motor: The phrenic nerve causes the diaphragm to contract when you inhale
Sensory: The phrenic nerve provides sensation to the central tendon of the diaphragm
Actions
Inhale
When the diaphragm contracts, it moves downwards, creating a vacuum in the chest cavity that pulls air into the lungs.
Exhale
When the diaphragm relaxes, it moves upwards, compressing the chest cavity and pushing air out of the lungs.
dome-shaped muscle that separates the thoracic cavity from the abdominal cavity
Peritoneum & Peritoneal Cavity
Layers
Parietal
The outer layer that attaches to the chest wall.
Visceral
The inner layer that covers the lungs, blood vessels, nerves, and bronchi
Formations
Mesentery
The mesentery is a fold of membrane that attaches the intestine to the wall around the stomach area and holds it in place.
Omentum
Greater
Fat deposition, having varying amounts of adipose tissue. Immune contribution, having milky spots of macrophage collections. Infection and wound isolation
Lesser
Connects liver to stomach
Subdivisions
Omental foramen
allows communication between the greater and lesser sacs of the peritoneal cavity
Omental bursa
Allows stomach to move freely
Quadrants
RUQ
right portion of the liver, gallbladder, right kidney, a small portion of the stomach, portions of the ascending and transverse colon, and parts of the small intestine
LUQ
left portion of the liver, the larger portion of the stomach, the pancreas, left kidney, spleen, portions of the transverse and descending colon, and parts of the small intestine
RLQ
cecum, appendix, right ovary (in females), right fallopian tube (in females), right ureter, the lower pole of the right kidney, portions of the ileum (small intestine), and various blood vessels and lymphatics, including branches of the abdominal aorta and iliac arteries.
LLQ
sigmoid colon, part of the descending colon, the left ovary (in females), the left fallopian tube (in females), the left ureter, portions of the small intestine (especially the ileum), and various blood vessels and lymphatics, including branches of the abdominal aorta and iliac arteries.
Thorax
Boundaries of thorax
Superior
1st rib
Inferior
Diaphragm
Lateral
Ribcage
Anterior
Sternum
Manubrium
Body
Xiphoid process
Posterior
12 thoracic vertebral bodies
Rib cage
Typical
3-10
Atypical
1,2,11,12
Head with 2 articular facets
Neck
The neck of a rib is the flattened part that connects the head of the rib to the body, or shaft
Tubercle
Attach to transverse process of T vertebrae
Shaft
The shaft of the rib cage is the body of the rib, which is a flat, curved, and thin bone
Costal groove
Superior aspect for neruo structures
provides an attachment site for the innermost intercostal muscle.
Angle of rib
an area of the body of tenth rib where its curvature changes sharply
located lateral to the tubercle and is marked by a prominent linear ridge on the ribs external surface
Paired ribs
Ribs 1-7 attach to sternum via cartilage
8-10 articulate with cartilage superior to them
11-12 are floating and not attached to anterior rib cage
Neurovascular supply
Paired internal thoracic artery and veins
a paired artery that supplies blood to the anterior chest wall, breasts, and upper abdomen
small paired vessel that drains blood from the chest wall, breasts, diaphragm, and part of the mediastinum back to the heart
Intercostal nerves: ventral rami of T1-T12
Posterior intercostal vessels
Posterior intercostal artery
The posterior intercostal arteries are a set of blood vessels that supply the chest wall, back, and spine:
Posterior intercostal vein
The posterior intercostal veins are a set of veins that drain the back of the thoracic cavity
Muscles
External intercostals
The posterior intercostal veins are a set of veins that drain the back of the thoracic cavity:
When you inhale, the external intercostal muscles contract, which raises and spreads the ribs apart, expanding the chest cavity and allowing the lungs to fill with air.
Internal intercostals
The internal intercostal muscles are located in the middle of the three intercostal muscle layers in the thorax, deep to the external intercostal muscles. They extend from the front of the ribs, around the back, and past the bend in the ribs.
The internal intercostal muscles contract to depress the ribs and push air out of the lungs during forced exhalation. They are also important for normal speech and singing.
Innermost intercostals
They are found in the middle two-thirds of the intercostal spaces, deep to the internal intercostal muscles and intercostal vessels and nerves.
They stabilize the ribs during normal breathing and depress the ribs during forced exhalation.
Transversus thoracis
Located on the inner surface of the anterior thoracic wall
Helps to depress the ribs during forced exhalation
Scalenes
Anterior middle- 1st rib
Posterior - 2nd rib
act as postural muscles in maintaining the position of the cervical tract or playing an active role in the movements of the neck
Mediastinum
Great Vessels
Pulmonary A/V
Pulm V
The pulmonary veins carry oxygen-rich blood from the lungs to the heart, where it is then pumped to the rest of the body
Pulm A
transport deoxygenated blood from the right side of the heart to the lungs for oxygenation
Aortic Arch
Between the ascending and descending aorta in the upper mediastinum
Distributes blood to the head and upper body, and helps regulate blood pressure
Superior vena cava
Carries blood from the head, neck, arms, and chest to the heart
In the superior and middle mediastinum
The right and left brachiocephalic veins join to form the SVC
Inferior vena cava
The IVC is located along the right side of the vertebral column and passes through the diaphragm.
The IVC's main function is to return blood from the lower body to the heart. The heart then pumps the blood to the lungs to pick up oxygen.
Thymus gland
The thymus gland's main function is to produce and mature T cells, a type of white blood cell that helps the body fight infection:
The thymus gland is located in the upper chest, in the mediastinum, between the lungs, and in front of and above the heart:
Trachea
Functions
The trachea's primary function is to allow air to pass into and out of the lungs.
Temperature regulation
Disease defense
Air filtration
Cartilage support
location
The trachea is located in the neck and upper chest, between the collarbones and below the larynx
Parts
Cartilage rings: The trachea is made up of circular cartilage rings that support the trachea and prevent it from collapsing when you exhale.
Mucosa: A substance that lines the cartilage rings.
Cricoid cartilage: A ring of cartilage that surrounds the trachea in the middle of the neck.
Larynx: The upper part of the trachea that contains the vocal cords.
Esophagus
Functions
The esophagus's primary function is to move food and liquids from the mouth to the stomach
Lubrication: The esophagus produces mucus to help food pass through.
location
The esophagus is a muscular tube in the center of the chest that connects the throat to the stomach:
The esophagus is located in the mediastinum, behind the trache and in front of the spine. It passes through the diaphragm and enters the abdominal cavity.
Sympathetic chain
network of nerve fibers that runs parallel to the vertebral column on either side of the body
Location: Extends from the base of the skull to the coccyx
Structure: Consists of 22 pairs of interconnected neuronal cell bodies
Regions: Divided into cervical, thoracic, lumbar, and sacral segments
Function: Carries preganglionic fibers from the spinal cord that synapse in ganglia, which then send postganglionic fibers to the viscera
Phrenic nerve
Function
The phrenic nerve controls the diaphragm's contraction and relaxation and provides sensory information about touch and pain to the diaphragm and surrounding tissues.
The phrenic nerve originates from the C3 through C5 nerve roots in the spinal cord.
The phrenic nerve travels through the neck and chest, past the heart and lungs, to reach the diaphragm.
Vagus nerve
Internal thoracic
artery
The ITA runs along the inner surface of the anterior chest wall, about 2–3 centimeters from the sternum and slightly medial to the nipple.
The ITA originates from the subclavian artery, a few centimeters below the origin of the thyrocervical trunk.
The ITA terminates at the level of the sixth rib, dividing into the superior epigastric and musculophrenic arteries.
vein
collects blood from the chest wall and breasts and returns it to your heart
Deep in the chest, near the sternum
Thoracic duct
The thoracic duct's primary function is to transport lymph from the body's tissues into the circulatory system:
courses posterior to the esophagus at the T7 level and crosses over the midline to the left side of the thorax around the T5 vertebral level.
Aorta
Descending
The descending aorta is the part of the aorta that runs from the aortic arch down through the chest and into the abdomen:
Ascending
The ascending aorta is the initial portion of the aorta that extends behind the sternum, ending at the level of the T4 vertebral body.
The ascending aorta is a key part of the circulatory system, helping the heart pump blood throughout the body.
Diaphragm
L/R Phrenic nerve
L
Left phrenic nerve: Controls the left side of the diaphragm
R
Right phrenic nerve: Controls the right side of the diaphragm
Central tendon
The central tendon is made up of multiple planes of fibers that intersect at various angles to form bundles that give it strength.
During inhalation, the central tendon is pulled down by the diaphragm, which expands the chest cavity and allows air to enter the lungs.
The vena caval foramen is an opening in the central tendon that allows the inferior vena cava and right phrenic nerve to pass through.
L/R crus and arcuate ligaments
Right crus: Originates from the first three lumbar vertebrae and intervertebral discs
Left crus: Originates from the upper two lumbar vertebrae and intervertebral discs.
openings
Caval opening
Inferior Vena Cava
The IVC's main function is to return blood from the lower body to the heart. The heart then pumps the blood to the lungs to pick up oxygen.
T8
Esophageal opening
Esophagus
move food and liquids from the mouth to the stomach.
Vagal trunks
Anterior vagal trunk
Supplies the abdominal esophagus, cardia, lesser curvature, and superior portion of the stomach. It also branches into the hepatic branch, which supplies the liver, gallbladder, and biliary apparatus.
Posterior vagal trunk
Supplies the foregut and midgut with visceral sensory and parasympathetic innervation.
T12
Aortic Hiatus
Desc. Aorta
The descending aorta is the part of the aorta that runs from the aortic arch down through the chest and into the abdomen:
Thoracic duct
The thoracic duct's primary function is to transport lymph from the body's tissues into the circulatory system:
Azygos vein
Located on the right side of the middle back of the chest, along the right side of the vertebral column
Part of the azygos venous system, which helps circulate blood and deliver oxygen and nutrients to tissues. The azygos vein also creates a collateral pathway between the superior vena cava (SVC) and the inferior vena cava (IVC).
T12
Cardiovascular system
Anatomy of the heart
Major vessels
Aortic Arch
R Brachiocephalic Trunk
R common carotid
Supplies blood to brain
R subclavian
supply oxygen-rich blood to the right upper extremity
L common Carotid
supplying oxygenated blood to the head and neck
L subclavian
supply oxygen-rich blood to the upper body, including the left arm, neck, head, and back of the brain
L coronary
Ant interventricular
supplies blood to the left ventricle, the interventricular septum, and a small section of the right ventricle's outflow tract
circumflex
Supplies oxygenated blood to the left atrium and the back and outer areas of the heart's left ventricle
R coronary
supplies blood to the bottom of the heart
Marginal
supplies the majority of the myocardium of the right ventricle of the heart.
Superior VC
Carries blood from the head, neck, arms, and chest to the heart
In the superior and middle mediastinum
The right and left brachiocephalic veins join to form the SVC
Inferior VC
The IVC is located along the right side of the vertebral column and passes through the diaphragm.
The IVC's main function is to return blood from the lower body to the heart. The heart then pumps the blood to the lungs to pick up oxygen.
Pulmonary trunk
L pulm artery
Supplies blood to left lung
R pulm artery
Supplies blood to right lung
Pulmonary Veins
L
The left pulmonary vein carries oxygenated blood from the left lung to the left atrium of the heart
R
the right pulmonary vein carries oxygenated blood from the right lung to the left atrium
Layers
Pericardium
positions the heart in the mediastinum and limits its motion while providing a lubricated slippery surface for the heart to beat inside and the lungs to move outside
Myocardium
Contraction: The myocardium contracts and relaxes rapidly and involuntarily to pump blood throughout the body.
Force generation: The myocardium generates enough force to supply the body's metabolic demands.
Coordination: The myocardium contracts in a coordinated fashion to resist fatigue.
Endocardium
keeps the blood flowing through the heart separate from the myocardium, or cardiac muscles
Chambers
R atrium
Right atrium: Receives blood from the body that's low in oxygen
R ventricle
Right ventricle: Pumps blood to the lungs to receive oxygen
L atrium
Left atrium: Receives oxygenated blood from the lungs through the pulmonary veins
L ventricle
Left ventricle: Pumps oxygenated blood to the aorta, which distributes it to the rest of the body
Valves
Tricuspid
Tricuspid valve: Located between the right atrium and right ventricle
Pulmonary
Pulmonary valve: Located between the right ventricle and pulmonary artery
Mitral/bicuspid
Mitral valve: Located between the left atrium and left ventricle
Aortic
Aortic valve: Located between the left ventricle and aorta
Physiology of the heart
cardiac cells
Characteristics
Automaticity
The heart's automaticity is the ability of cardiac cells to spontaneously generate electrical impulses, or action potentials without external stimulation
Rhythmicity
The heart's rhythmicity is the ability of the cardiac muscle to depolarize and repolarize in a stable and repetitive manner
Excitability
Cardiac excitability is the ability of heart cells to depolarize and repolarize and to propagate electrical activity to other cells
Conductivity
The heart's conductivity refers to the ability of its cells to generate and conduct electrical impulses that control the heartbeat:
Contractility
Cardiac contractility is the heart's ability to contract and pump blood. It's also known as inotropy.
types
Autorhythmic
Generate action potentials
1%
-60mV pacemaker potential
Contractile
respond to action potentials
-90 mV resting membrane potential
99%
Conduction system
SA node
right atrium
initiates depolarization and sets HR
Av node
Subtopic
Slows down conduction to allow atrial contraction
Bundle of His and purkinje fibers
spread electrical signal to ventricles
Cardiac cycle
Mechanical events
Systole
Contraction
Atrial kick
Diastole
Relaxation
passive filling of ventricles
70% of blood volume
Phases
Late diastole
both atria and ventricle are relaxed
Atrial systole
atria contracts
additional blood enters ventricles
Isovolumetric ventricular contraction
ventricles contract
all valves are closed (no ejection)
Ventricular ejection
Semilunar valves are open
blood is ejected into arteries
Isovolumetric relaxation
ventricles relax
all valves closed
residual blood remains (end systolic volume
EKG
P wave
Atrial depolarization
QRS complex
Ventricular depolarization
T wave
Ventricular repolarization
Cardiac output
Stroke volume
Amount of blood pumped by one ventricle in contraction
ejection fraction - % of EDV ejected with one
contraction
Equation
HR x SV
Factors
Frank-Starling
Incr stretch= incer contraction force
Venous return
skeletal muscle pump, respiratory pump
Neural influence
PNS
Reduces HR (acetylcholine)
SNS
Increases HR and contractility (Epi and norepi)
Heart sounds
First sound
AV valves closing
Second sound
Semilunar valves closing
Blood
Function
Transport vital substances
remove metabolic waste
pathogen defense
temperature regulation
Flow
Factors effecting blood flow
Pressure gradient
high to low pressure
Friction force
Less friction = better flow
Diameter
Greater diameter = better flow
Length
Shorter vessel length = better flow
Viscosity
incr in viscosity = decr cardiac output
Pressure
Systolic: The highest pressure when the heart beats
Diastolic: The lowest pressure between heartbeats
Respiratory system
Anatomy
Trachea
L & R bronchi
Secondary bronchi
Tertiary bronchi
Alveoli
Lobes
physiology
Functions
Gas excahnge
Exchange 1
Pulm ventilation
and alveolar ventilation
Exchange 2
Gas exchange between alveoli
and lung capillaries
Exchange 3
Gas exchange between
blood and tissues
Transport
Movement of O2 and CO2 in
blood
Protection
Conditioning of air
Warming
To body temp
Humidifying
Add water vapor
Against pathogens
Ciliated epithelium in watery saline layer
Sticky layer of mucous over cilia to trap large particles
Ph regulation
controlling the amount of carbon dioxide (CO2) exhaled
Vocalization
Voice is generated by airflow from the lungs. When the air from the lungs blows through the vocal folds
Ventilation
Gas laws
High to low pressure
Boyle's law
How changes in lung volume affect air pressure
during breathing
Dalton's law
How gases are exchanged in respiratory system
Lung volumes and capacity
Factors
Airway resistance
viscosity of air
Diameter of airways
Minute ventilation
Patterns of ventilation
Respiration (gas exchange)
Hypoxia
Oxygen availabilty
Transfer efficiency
Perfusion
Respiratory control mechanisms
Chemoreceptors
Medulla
Sensitive to cerebrospinal CO2
Periphrail
Responds to PO2, PCO2
and pH changes
Brain stem control
Pons and medulla regulate respiration
Neuronal influence
Conscious and unconscious can effect breathing rates
Gas transport
O2 transport
Hemoglobin
Binds up to 4 O2 molecules
98% of O2 transport
CO2 transport
Bicarbonate
about 70% of CO2
Hemoglobin bound CO2
23%
Plasma CO2
7% dissolved directly
Oxy-hemoglobin binding curve
Ph
Temp
PCO2