Module 1 Flashcards
sagittal plane
divides the body into left and right halves
median plane
- mid-sagittal plane
- except in the hands and feet
- — goes through the third digit
anatomical position
facing forward, with feet and palms forward
parasagittal plane
parallel to the median (mid sagittal) plane
frontal (coronal) plane
passes through the body at any level and divides the body into front and back
transverse (horizontal) plane
passes through the body at any level and divides the body into upper and lower portions
1a. superior
1b. inferior
2a. rostral
2b. caudal
3a. cephalic
- going to the top of the body
1b. going to the bottom of the body
2a. same as 1a
2b. same as 1b
3a. same as 1a
1a. anterior
1b. posterior
2a. ventral
2b. dorsal
1a/2a. to the front/belly
1b/2b. to the back
1a. medial
1b. lateral
1a. to the mid-sagittal plane
1b. away from the mid-sagittal plane
1a. proximal
1b. distal
1a. toward the trunk of the body
1b. away from the trunk of the body
these terms are used to refer to the limbs/extremities
1a. palmar
1b. dorsal
refer to the hands
1a. palm of the hand
1b. back of hand
1a. dorsal
1b. plantar
refer to the feet
1a. top of the foot
1b. sole of the foot
1a. extrinsic
1b. intrinsic
refer to muscles
1a. has an attachment outside the region of interest and one inside the region
1b. has both attachments inside the region of interest
1a. valgus
1b. varus
- used for the extremities
- refers to the bone distal to a joint
- — and its angle of deviation from the midline
1a. the bone distal to the joint deviates away from the midline - — ex: feet splayed out from knees
1b. the bone distal to the joint deviates toward the midline - — ex: the feet are farther in than the knees, like a ballet plie
1a. superficial
1b. deep
1a. external, towards the periphery
1b. toward the interior
- bilateral
- unilateral
- ipsilateral
- contralateral
- occurs on both sides
- occurs on one side
- on the same side as…
- on the side opposite to…
ipsilateral and contralateral require a point of reference
1a. flexion
1b. extension
- describe an arc of motion occurring in a sagittal plane
- descriptions usually include the name of the joint, bone, or body part (ex: shoulder, humerus, arm)
1a. a bending movement around a joint in a limb (as the knee or elbow) that decreases the angle between the bones of the limb at the joint
1b. an unbending movement around a joint in a limb (as the knee or elbow) that increases the angle between the bones of the limb at the joint
- lateral flexion
2. rotation
refer to movement of the vertebral column
- -motion in a coronal plane
- lateral flexion of the trunk: moving your body from side to side - moving your body circularly
1a. abduction
1b. adduction
Coronal Plane
1a. movement away from the body
1b. movement toward the body
Horizontal Plane (ex: arm pointing straight out)
1a. movement away from the body
1b. movement across the body
1a. medial (internal) rotation
1b. lateral (external) rotation
1a. rotating in an arc toward the center of the body
1b. rotating in an arc away from the center of the body
1a. elevation
1b. depression
1a. movement up
1b. movement down
1a. protrusion
1b. retrusion
specific to the mandible/jaw
1a. jutting the jaw out
1b. pulling the jaw back
1a. supination
1b. pronation
specific to the arms/hands
1a. spinning the hand so the palm is facing up
1b. spinning the hand so the palm is facing down
1a. opposition
1b. reposition
specific to the hands
1a. bringing the thumb and pinky together across the hand
1b. opening the hand by putting the thumb and pinky back on the sides
1a. dorsiflexion
1b. plarflexion
specific to the ankle/foot
1a. flexion of the ankle upward, pulling the toes up toward the shin
1b. flexion of the ankle downward, pointing the toes toward the floor
1a. inversion
1b. eversion
- specific to the ankle/foot
- the ankle does not rotate nearly as much as the arm/wrist
1a. twisting the foot so the big toe is up and the sole faces inward to the midline
1b. twisting the foot so the pinky toe is up and the sole faces outward away from the body - —like when you have worn down a pair of shoes from putting too much weight on the inside of your foot
Bone Function
- protection for vital structures
- support for the body
- the mechanical basis for movement
- storage for salts (eg calcium)
- a continuous supply of new blood cells
- — made in bone marrow
Number of bones in the skeleton
206 bones
Classification of Bones by Location
- Axial
- —- skull, vertebra, sternum, ribs
- —- bones on the midline
- Appendicular
- — bones on the appendages, extremities
- — pelvis, scapula, arms, legs
Classification of Bones by Shape
- Long - humerus
- Short - carpal bones
- Irregular - vertebra
- Flat - skull
Classification of Bones by Structure (Microscopic)
- Compact/Cortical
- Spongy/Trabecular
Skeletal Articulations
- where bones come together
- joints
Types of Joints
- Fibrous (synarthroidal)
- — suture, syndesmosis, gomphosis
- Cartilaginous or Fibrocartilaginous (amphiarthosis)
- — synchondrosis, symphysis
- — cartilege between bones
- Synovial
Suture
- fibrous joint
- found between flat bones of skull
Syndesmosis
- fibrous joint
- ex: ulna and radius
- thin sheet between bones
Gomphosis
- fibrous joint
- shaped like a peg
- found only in the maxilla and mandible where the teeth fit into them
Synchondrosis
- primary cartilaginous joint
- — part of the development process
- ex: growth plate in long bones
- — during development there is cartilage between the end and the shaft of the bone
- — after growth, these fuse into one bone as the cartilage ossifies
Symphysis
- secondary cartilaginous joint
- not part of the development process
- persists in the grown skeleton
- ex: pubic symphysis
Synovial Joint
- fluid between two bones
- — allows the bones to more smoothly against each other
- joint capsule of fibrous tissue that encloses the ends of both bones
- —- encloses the joint cavity (space between bones)
- — synovial membrane lines capsule and continually produces fluid that fills the space
- articular ends of the bone (part at the joint) are covered in hyaline cartilage
- — hyaline is very smooth cartilage so it helps with smooth movement
Types of Synovial Joints
- classified by articular shape and axes of movement
- Plane (Gliding)
- — bones meet at a very flat surface
- Uniaxial
- — hinge and pivot
- – move around a single axis
- Biaxial
- — can move in two planes
- — condyloid: base of fingers (knuckles), can go in flexion/extension and abduction/adduction
- — saddle: thumb, can go in flexion/extension and abduction/adduction
- Triaxial
- — ball and socket
- — shoulder is capable of flexion/extension, abduction, adduction, and internal/external rotation
Accessory Structures Associated with Joints
- fibrocartilagenous disks
- plates
- menisci
- ligaments
- bursae/tendon sheath
Bursae/ tendon sheath
- a flattened sac with fluid in it
- — made of connective tissue
- facilitate movement by decreasing friction between adjacent structures
- tendon sheaths wrap around a tendon while bursae are just there
Ligaments
- connect bones to bones
- intrinsic: begin and end within the joint capsule
- extrinsic: have an attachment in the joint and an attachment outside of the joint
Nerve and blood supply to joints
- periarticular arterial anastomoses: network of oxygenated blood supply going to a joint
- mechanoreceptors in joints
- — nerves
- — transmit information to the central nervous system about the position of the joint
- — proprioception: the sense of the position of the joints
- Hilton’s Law
Hilton’s Law
- where the blood and nerves come from to go to a joint
- the blood supply and nerves to a joint are from the same vessels/nerves that supply the muscles around the joint
Rheumatoid Arthritis
- inflammation of the synovial joints
- autoimmune disorder
- — body attacks its own synovial membranes
- symmetric: break down of the synovial membranes equally on both sides of the body
Osteoarthritis
- wear on the joint surfaces
- related to activity
- — caused by wear and tear
- may be unilateral: may only have breakdown on the joints on one side of the body if you only overuse the one hand/shoulder/etc
Types of Muscle
- Cardiac
- Skeletal
- Smooth
Muscle: cardiac
- heart muscle and adjacent great vessels
- short branching fibers
- continuous rhythmic contraction
- involuntary contraction
- — nervous system modifies the rate/strength of contraction
- — but the contraction is automatic
Muscle: smooth
- small, spindle-shaped fibers without striations
- walls of hollow organs, blood vessels, iris, attached to hair follicles
- weak contraction
- involuntary control
- — uses the autonomic nervous system
Muscle: skeletal
- related to joints and connective tissue
- large, long unbranched fibers
- striations
- strong contractions: produce movement
- voluntary or reflexive
- — mostly under direct voluntary control
- – exceptions are the reflexes
- innervate by peripheral nerves
Motor Unit
- motor neuron axon form a junction with individual muscle fibers
- the motor unit is the motor neuron axon plus the fiber it connects to
Skeletal Muscle Organization
- fascia divides regions into compartments
- — fascia are broad sheets of connective tissue
- an individual compartment usually has its own nerve and blood supply
- — a nerve cannot cross through fascia to get to another compartment
Muscle: gross architecture
- Multipennate: muscle fibers from a lot of different directions that meet at one point
- — muscle can contract in a lot of different ways
- Quadrate muscle: forms a square with all the fibers going in one way
- — muscle can only contract and apply force in one way
Muscle Action
- origin
- insertion
- proximal attachment, the attachment that stays in place when the muscle contracts
- distal attachment, the attachment that moves when the muscle contracts, the attachment moves toward the origin
Tendon
- connects the muscle to the bone
For each muscle know the…..
- Two Attachments
- — do not need to know which is origin and which is insertion
- — if multiple origins or insertions, need to know all of them
- Action of the Muscle
- Innervation of the Muscle
- — which nerve goes to it
- — which compartment the muscle is in tells you which nerve innervates it
Neuron
- basic unit for cellular processing in the nervous system
- information processing
- Components:
- — dendrite, soma/cell body, axon
- — information is typically received through the dendrites and passed through the soma down the axon
Dendrite
- receives information from other neurons via synapses and carries the signal towards the soma
Soma
- supports the metabolic and synthetic needs of the neuron
- integrates electrical signals
- — although final integration occurs at axon hillock
Axon
- conducts information away from the cell body via an electrical signal called an action potential
Neurons: classification by direction of information flow
- Efferent: motor neurons
- Afferent: sensory or receptor neurons
- Interneurons: relay neuron, association neuron
Efferent Neurons
- motor neurons
- carry nerve impulses away from the central nervous system to effectors such as muscles or glands
Afferent Neurons
- sensory or receptor neurons
- info about the environment such as touch and pain
- carry nerve impulses from receptors or sense organs toward the central nervous system
Interneurons
- relay neuron, association neuron
- communicates only to other neurons
- all processes confined to a small area of the central nervous system
- most numerous types of neuron
Structural Division of the Nervous System
- Central Nervous System
- — Brain and Spinal Cord
- Peripheral Nervous System
- — 12 pairs of cranial nerves
- — 31 pairs of spinal nerves
- — all the nerves that come off the brain and spinal cord
CNS: meninges
- Three connective tissue layers from superficial to deep that help to protect the brain
- — Dura Mater
- — Arachnoid Mater
- — Pia Mater - directly on top of the brain
Meninges and the Spaces from superficial (skull) to deep (brain)
- Skull
- Epidural Space
- Dura Mater
- Subdural Space
- Arachnoid Mater
- Subarachnoid Space
- Pia Mater
- Brain
Brain
- Bilateral Hemispheres: right and left
- connections between the hemispheres
- — allow the two sides to communicate and coordinate actions
- fluid filled ventricles
- — filled with cerebral spinal fluid which helps nourish the brain
- — constantly being produced
- — cerebral spinal fluid also fills the subarachnoid space
Spinal Cord
- Contains all the motor neurons supplying all skeletal muscle as well as most autonomic efferent neurons (anterior)
- It receives all of the sensory input from the body and some from the head (posterior)
- Not uniform in diameter
- — enlarged regions in cervical and lumbar regions because there are more neurons going out to the upper and lower extremities
- Terminates at the vertebra L1-L2, not at the end of the vertebral column
- — conus medularis: end of the spinal cord
Spinal Cord Blood Supply
- has a rich blood supply
- one anterior spinal artery
- — supplies the anterior two thirds of the spinal cord
- two posterior spinal arteries
- — supply the posterior one third of the spinal cord
Spinal Cord Segments
- specific regions along the vertebral column
- — 31 total
- 8 cervical - enlarged
- 12 thoracic
- 5 lumbar- enlarged, conus medullaris at L1-L2
- 5 sacral
- 1 coccygeal
Spinal Cord Meninges
- Dura Mater
- Arachnoid Mater
- Pia Mater
- — denticulate ligaments: extension of pia that stabilize the spinal cord
- — filum terminale: a longitudinal extension of the pia mater that stabilizes the spinal cord in a vertical direction, attaches to the conus medullaris and the sacrum
Spinal Taps and Epidural Anesthesia
- insert a needle to the subarachnoid space where the cerebral spinal fluid is
- enter the needle below the L1-L2 so that you cannot injure the spinal cord
Peripheral Nervous System
- transmits info to and from the CNS
- Cranial Nerves
- — 12 pairs
- — originate from the brainstem
- — comprised of both sensory and motor fibers
- Spinal Nerves
- — 31 pairs: one pair off each segment of the spinal cord
- — originate from the spinal cord
- — comprised of both sensory and motor fibers
Spinal Roots and Nerves
- Posterior Roots: sensory neurons
- Anterior Roots: motor neurons
- anterior and posterior roots come together to form the Spinal Nerve
- — the spinal nerve has both motor and sensory components
Anterior and Posterior Rami
- each spinal nerve gives rise to an anterior and posterior ramus
- Dorsal Ramus: to deep back muscles/skin, to the posterior
- — mixed neurons - both sensory and motor
- Ventral Ramus: to the trunk/limbs, to the anterior
- — mixed neurons - both sensory and motor
Intervertebral Foramen
- the spinal nerves exit the vertebral canal via intervertebral foramen which are formed between adjacent vertebrae
Dermatome
- the area of skin innervated by a single spinal cord segment via its spinal nerve
- — all spinal nerves are a mix of sensory and motor neurons
- use to determine where spinal cord/nerve damage is by poking the skin and asking where the patient can or cannot feel the pressure
- — use a map of which spinal cord segments send nerves to what regions of skin
Myotome
- consists of all the striated muscle fibers innervated by a given spinal cord segment via its spinal cord
- — all spinal nerves are a mix of sensory and motor neurons
- used to determine where spinal cord/nerve damage is by asking the patient to perform a series of motions
- — if the patient cannot, the spinal nerve/cord segment that goes to that muscle group is probably damaged
Functional Subdivisions of the Nervous System
- Somatic
- Autonomic (Visceral)
- — Enteric
- — Sympathetic
- — Parasympathetic
Somatic Nervous System
- innervates skin and most muscles
- mainly involved in receiving and responding to info from the external environment
Autonomic Nervous System
- innervates organ systems and other visceral elements in peripheral regions of the body
- concerned with detecting and responding to info from the internal environment
- Subdivisions
- — Parasympathetic: rest or digest
- — Sympathetic: fight or flight
- — Enteric: innervates walls of digestive system
Vertebral Column: Component Parts
- 33 vertebrae
- — 26 in mature adult
- 7 cervical
- 12 thoracic
- 5 lumbar
- 3-4 coccygeal
Typical Vertebra
- Body
- Seven Processes
- — one spinous
- — two transverse
- — four articular: two superior, and two inferior
- Two Pedicles: one on each side, connect the vertebral body and the transverse process
- Two laminae: one on each side, connect the transverse process to the spinal proccess
Vertebra Assembled
- the inferior articular process of a vertebra forms a joint/connection with the superior articular process of the vertebra below it
- — zygapophyseal joints (synovial plane joint)
- the rings of processes form the vertebral canal when stacked
- — the spinal cord runs through the canal
- intervertebral discs are between the bodies of stacked vertebra
Joints of the Vertebral Bodies
- Symphyses (secondary cartilaginous joints)
- — designed for weight bearing and strength
- the articulating surfaces of adjacent vertebra are connected by IV discs and ligaments
Intervertebral Foramina
- each spinal nerve exits the vertebral canal laterally through an intervertebral foramen
- intervertebral foramen are formed between each vertebral arch and the adjacent zygapophyseal joint
Intervertebral Disc
- outer concentric rings of fibrous cartilage
- — anulus fibrosus
- center is a more jelly like substance
- — nucleus pulposus
- absorb shock
- permit movement between adjacent vertebrae
Back Pain: herniated disc
may be due to
- disc degeneration
- excessive weight
- improper lifting
- usually found at lumbar region
There are only 7 cervical vertebra and 8 cervical nerves…. so how does numbering work?
- the first nerve exits above the first cervical vertebra
- — following it, C1-C7 exit above their corresponding vertebra
- C8 exits below the 7th cervical vertebra
- all following nerves (T1, etc) exit below their corresponding vertebra
Sacrum
- usually composed of five fused sacral vertebrae in adults
- provides strength and stability to the pelvis and transmits the weight of the body to the pelvic girdle
Coccyx
- small triangular bone that is usually formed by fusion of the four rudimentary coccygeal vertebrae
Curvatures
- Primary
- — concave anteriorly )
- — thoracic and sacral
- Secondary
- — convex anteriorly (
- — cervical
- — lumbar
Abnormal Curvatures
- Kyphosis: abnormal anterior
- Lordosis: abnormal posterior
- Scoliosis: lateral curvature
Movement of the vertebral column
- Flexion: bend to touch toes
- Extension: bend backward
- Lateral Flexion: bend/stretch to the side
- Rotation: twisting the trunk to the sides
Spina Bifida
- two halves of the vertebra that are supposed to come together to form the spinous process don’t meet
- a gap/opening is formed
- Congenital
- — Spina Bifida Occulta
- — Meningocele
- — Myelomeningocele
Spina Bifida Occulta
- very small gap
- no symptoms
- usually picked up for some other reason
Spina Bifida
- Meningocele
- Myelomenigocele
- the opening is large enough for the meninges to come out
- the opening is large enough for the meninges and spinal cord to come out
- – result similar to a spinal cord industry: loss of function in area below the lesion
Intrinsic Muscles of the back
- movement of the vertebra
- Superficial Group
- Intermediate Muscles
- — Erector Spinae Group
Back Muscles: Superficial Group
- Splenius Cervicis and Splenius Capitis
- located at the back of the neck
- Att: spinous processes of T3-T6
- Att: transverse processes of C1-C3/4
- Act:
- — bilateral: extension
- — unilateral: lateral flexion and rotation to the same side
- Ner: dorsal rami of lower cervical nerves
Back Muscles: Intermediate Muscles - Erector Spinae Group
- Spinalis, Longissimus, Iliocostalis
- — listed from shortest and most medial to longest and most lateral
- Att: posterior iliac crest and sacrum, sacral and inferior lumbar spinous processes, supraspinous ligament
- Att:
- — Spinalis: spinous processes in upper thoracic and cervical regions
- — Longissimus: ribs, thoracic and vertebral transverse
Thoracic Cage Components
- 12 thoracic vertebrae and discs
- 12 pairs of ribs and their costal cartilages
- sternum
Thoracic Cage Function
- protection of the heart and lungs
- attachment site for many muscles
- – including the muscles of respiration
Typical Rib (3-9)
- Head
- — 2 facets on the end: site of articulation with corresponding vertebra and vertebra superior to it
- — posterior end, not the end with cartilage
- Neck
- — small section between the head and tubercle
- Tubercle
- — has an articular facet for association with corresponding vertebra
- Angle: rib turns anterolateral
- Costal Groove
- — location of intercostal nerve, artery, and vein, protects them
- — indentation on the internal surface of the rib
Costovertebral Joints
- synovial plane joints
- each rib articulates with the body of the vertebra with the same name and the one above it
- —- ex: 7th rib articulates with vertebral body of T7 and vertebral body of T6
- each rib articulates with the transverse process of the corresponding vertebra
- — ex: 7th rib articulates with the transverse process of vertebra T7
Ribs
- 12 pairs of ribs
- True Ribs: 1-7
- — their costal cartilage (hyaline) articulates with the sternum
- False Ribs: 8-10
- — their costal cartilage articulates with the costal cartilage of the ribs above them, not directly with the sternum
- Floating Ribs: 11-12
- — no attachment to the sternum
- Costal Margin
- — a landmark that can be palpated to check the health of underlying organs
- — the area on the front side of the ribs past the sternum where it is all cartilage
Sternum
- Manubrium
- Body
- Xiphoid Process
Manubrium
- top part of the sternum
- jugular notch = suprasternal notch: dip on the top of the manubrium
- Manubriosternal joint/ sternal angle
- — symphysis
- — marks the end of the manubrium
Body of the Sternum
- costal notches: where the cartilage of the ribs join
Xiphoid Process
- end of the sternum
- xiphisternal joint
- — synchondrosis
- — where the body ends and the xiphoid process begins
Pectoralis Major
- muscle on the anterior thoracic wall
- Att: sternum, clavicle, upper ribs
- Att: humerus
- Ner: medial and lateral pectoral nerves
- Act:
- — main action on upper extremity
- — accessory muscle of respiration with forced inspiration
Serratus Anterior
- muscle on the anterior thoracic wall
- runs the length of the ribs
- Att: anterior aspect of the ribs
- Att: medial border of the scapula
- Ner: long thoracic nerve
- Act:
- — main action on upper extremity
- — accessory muscle of respiration with forced inspiration
Pectoralis Minor
- muscle on the anterior thoracic wall
- — deep to the pectoralis major
- Att: costal cartilage of ribs 3-5
- Att: corocoid process of the scapula
- Ner: medial pectoral nerve
- Act: accessory muscle of respiration with forced inspiration
Intercostal Muscles
- muscles in the anterior thoracic wall
- — deep dissection
- muscle fibers run vertically
- three layers
- — External Intercostal: fibers are about 45 deg toward medial
- — Internal Intercostal: fibers are about 45 deg toward lateral, assist in expiration
- — Innermost Intercostal: vertical fibers
- Att:
- Att:
- Ner: ventral rami of the thoracic spinal nerve
- — ventral rami come forward and become intercostal nerves
- — travel on the costal groove
- Act: muscles of respiration, help the diaphragm, provide tone of the rib cage
Intercostal Arteries
- posterior: arise from the aorta
- anterior: arise from the internal thoracic artery
- — a branch of the subclavian artery
- runs along the costal groove of the ribs
Diaphragm
- primary muscle of respiration
- responsible for the change in pressure that fills the lungs with air
- — descends during inspiration
- dome shaped muscle attached to costal margin
- Nerv: phrenic nerve which originates from C3, C4, and C5
- separates the thoracic and abdominal cavity
- — but some structures need to get from one cavity to the other so you need holes
Diaphragm Apertures
- some structures need to get from one cavity to another so you need openings
- Caval Opening (T8): allows for inferior vena cava to ascend into the thoracic cavity
- Esophageal Hiatus (T10): allows the esophagus to descend into the abdominal cavity
- Aortic Hiatus (T12): the descending aorta passes through to the abdominal cavity
Movement of the Thoracic Cage During Respiration
- moves at the synovial joints between the ribs and the vertebral transverse processes
- Inspiration: rib cage expands in a medial-lateral direction and elevates
- Expiration: reverse of inspiration
Thoracic Cavity Regions
- Two pulmonary cavities
- — one on each side
- — contain the pleura and the lungs
- Mediastinum: contains the heart
- —- located between the pulmonary cavities
Characteristic of a Lung
- Apex: top of the lung
- — superior to the first rib
- Three surfaces:
- — costal: adjacent to the ribs, the front of the lung
- — mediastinal: adjacent to the mediastinum, the medial side of the lung
- — diaphragamatic: adjacent to the diaphragm, bottom of the lung
Right Lung
- three lobes
- — superior: top half
- — middle: little one on the medial side
- — inferior: bottom half
- two fissures
- — oblique: separates superior/middle from inferior
- — horizontal: separates superior from middle
Left Lung
- two lobes
- — superior, inferior
- one fissure
- — oblique: separates superior and inferior lobes
Roots of the Lungs
- aka hilum of the lung
- centered on the mediastinal surface
- where major structures are located
- — primary bronchus
- — pulmonary artery and bronchial artery
- — pulmonary veins
Structure of the Pleura
- a two layered sac that surrounds but does not contain the lungs
- — there is some fluid between the two layers
- — the fluid filled space between layers is the pleural cavity
- visceral pleura: invests the lungs, including within the fissures, inner layer
- parietal pleura: lines the thoracic wall, outer layer
- — parts of the parietal pleura are named for where they adhere (ex: costal, mediastinal, diaphragmatic)
Function of the Pleura
- decrease friction between the lungs and the ribs during inspiration
- function is similar to that of a bursa
Pleural Cavity
- the potential space between the two layers of pleura
- contains pleural fluid to allow parietal and visceral pleura to slide smoothly against each other during respiration
Pulmonary Circulation
- the pulmonary trunk from the right ventricle of the heart divides into right and left pulmonary arteries, which transport poorly oxygenated blood to the lungs
- — the lungs oxygenate the blood
- the pulmonary arteries subdivide into lobar and segmental arteries within the lungs
- after passing through the pulmonary capillaries where gas exchange occurs ,the blood drains into pulmonary veins which return the well-oxygenated blood to the left atrium of the heart
Middle Mediastinum: Heart
- apex of the heart is at the fifth left intercostal space
- — the apex is at the bottom of the heart
Pericardium
- Inner: Serous
- — two layer sac which surrounds the heart
- — visceral layer closest to heart
- — parietal layer
- — a little bit of fluid is between the layers
- Outer: Fibrous
- — surrounds the serous pericardium
Cardiac Tamponade
- compression of the heart due to fluid accumulation in between the layers of the pericardium
- heart is not able to expand to pump efficiently
- life-threatening emergency
Major Features of the Heart
- 4 chambers
- — right and left atrium
- — right and left ventricle
- Valves
- — tricuspid: between right atrium and right ventricle
- — pulmonary: between right ventricle and pulmonary trunk
- — mitral: between left atrium and left ventricle
- — aortic: between left ventricle and aorta
Right Atrium Features
- Pectinate Muscles
- Crista Terminalis
- Opening of Coronary Sinus
- Fossa Ovalis
- Right Auricle
Pectinate Muscles
- ridges in the wall of the atrium (anterior heart wall)
- direct blood flow toward the ventricles
Crista Terminalis
- transition between the smooth walls of the posterior heart wall and the muscular anterior wall
- — the muscular wall is the pectinate muscles of the atrium
Opening of Coronary Sinus
- receives venous blood from the heart
- located inferior to and smaller than the fossa ovalis
Fossa Ovalis
- closed depression
- closes at birth, but open before then
- — no need for fetal blood to go to the lungs because the baby is not breathing air
- — before birth, the blood goes directly from the right to left side of the heart through the foramen ovale
- — at birth, a membrane forms over the foramen ovale and this forms the fossa ovalis
Right Auricle
- can be filled with blood to increase the capacity of the atrium
- like a spare room for extra space if needed
Right Ventricle
- Chordae Tendinae
- Papillary Muscles
- Trabeculae Carnae
- Moderator Band
- Tricuspid Valve
- Pulmonary Valve
Papillary Muscles
- in the wall of the ventricle and attach to the chordae tendinae
- contract and pull on the chordae tendinae to stabilize the valve
Trabeculae Carnae
- muscular ridges in the ventricle
Chordae Tendinae
- strings hanging from the valve into the ventricle
- stabilize valve cusps
- found in the tricuspid and mitral valves
Moderator Band
- band of tissue on the posterior wall of the ventricle
- introduce the impulse for contraction into the ventricle
- part of the conduction system of the heart
Left Atrium Features
- Pectinate Muscles
- Crista Terminalis
- Fossa Ovalis
- Right Auricle
- NO opening for the coronary sinus
Left Ventricle Features
- Chordae Tendinae
- Papillary Muscles
- Trabeculae Carnae
- Moderator Band
- Mitral Valve
- Aortic Valve
Cardiac Cycle
- deoxygenated blood returns from the body through the inferior and superior vena cava to the right atrium
- right atrium –> tricuspid valve –> right ventricle –> pulmonary valve –> pulmonary trunk –> pulmonary arteries –> lungs –> blood is oxygenated
- oxygenated blood –> pulmonary veins –> left atrium –> mitral valve –> left ventricle –> aortic valve –> aortic arch
- aortic arch –> head and neck
- aortic arch –> descending aorta –> rest of the body
Coronary Arteries
- the heart needs a blood supply, does not just pick up blood going through it
- coronary arteries supply oxygenated blood to the heart, perfuse the heart muscle
- aorta –> right coronary artery –> sinoatrial nodal artery, right marginal artery, posterior interventricular artery
- aorta –> left coronary –> anterior interventricular (LAD), circumflex artery
Venous Drainage of the Heart
- return deoxygenated blood back to the right atrium
- Coronary sinus: the final collecting vessel which gets all the deoxygenated blood from the heart muscle
- — drains into the right atrium
Coronary Artery Bypass Graft
- CABG
- a procedure when a coronary artery is blocked, impeding blood flow to the heart
- a vessel is inserted between the aorta and the distal end to the artery after the blockage
- restore circulation to the muscle of the heart