SHEEP HEART LAB

Walls of right atrium

The inside of the posterior wall is smooth but the inside of the anterior wall is rough due to pectinate muscles which extend into the auricle

Interartrial septum

Between the right and left atria, a feature is the fossa ovalis

Fossa ovalis

A remnant of foramen ovale during prenatal and is used to refer to the same structure in postnatal

Foramen ovale

Its function was to connect the right atrium to the left atrium so that the oxygenated blood from the mother can be mostly in the circuit. This is because the lungs are not functional before birth

Pectinate muscles

They increase the surface area of the right atrium to handle volume changes. They are more common in the right atrium than the left

Trabeculae carnea

A series of ridges in the ventricles formed by raised bundles of cardiac muscle fibres. It aids in the conduction system of the heart and prevents suctioning in the ventricles

Walls of left atrium

The inside of the posterior and anterior wall is smooth because the pectinate muscles confined to the left auricle in the left atrium. This is because it receives less variation in blood flow

Ductus arteriosus

A temporary blood vessel in prenatal and results in oxygenated blood from the placenta flowing from the pulmonary trunk to the aorta, bypassing the non functional lungs

Ligamentum arteriosum

A remnant of ductus arteriosus during prenatal and is used to refer to the same structure in postnatal

Left coronary artery

This passes inferior to the left auricle and dived into the anterior interventricular and circumflex branches

Anterior interventricular branches

It is in the anterior interventricular sulcus and supplies oxygenated blood to the walls of both ventricles

Circumflex branches

It is in the coronary sulcus and supplies oxygenated blood to the walls of the left ventricle and atrium

Right coronary artery

Supplies oxygenated blood via atrial branches to the right atrium. It continues inferior to the right auricle and dived into the posterior interventricular and marginal branches

Posterior interventricular branches

It is in the posterior interventricular sulcus and supplies oxygenated blood to both ventricles

Marginal branches

Goes beyond the coronary sulcus and runs along the right margin of the heart to supply oxygenated blood to the wall of the right ventricle

Anastomoses

Connections in the body where two or more arteries supply blood to the same region, causing a connection

Collateral circulation

Anastomoses provide alternate routes for blood to reach a particular area or organ, providing detours or other pathways if the main pathway is blocked

Coronary sinus

A large vascular (thin walled with no smooth muscle to alter diameter) sinus in the coronary sulcus on the posterior surface of the heart where most of the deoxygenated blood from the myocardium empty. This empties directly into the right atrium

Great cardiac vein

In the anterior interventricular sulcus that empties areas of the heart supplied by the left coronary artery (both ventricles and left atrium)

Middle cardiac vein

In the posterior interventricular sulcus that empties areas of the heart supplied by posterior interventricular branch of the right coronary artery (both ventricles)

Small cardiac vein

In the coronary sulcus and empties the right atrium and auricle

Anterior cardiac veins

Drains the right ventricle and empties directly into the right atrium

Superior

Towards the head, upper part of the structure

Inferior

Away from the head, lower part of the structure

Anterior (Ventral)

Nearer to or at the front of the body

Posterior (dorsal)

Nearer to or at the back of the body

Medial

Nearer to the midline

Lateral

Farther from the midline

Intermediate

Between two structures

Ipsilateral

On the same side of the body as another structure

Contralateral

On the opposite side of the body as another structure

Proximal

Nearer to the origination of a structure

Distal

Away from the origination of a structure

Superficial

Towards or on the surface of the body

Deep

Away from the surface of the body

Midsagittal or median plane, midline

A parallel plane that divides the body into equal right and left halves

Parasagittal plane

A parallel plane that divides the body into unequal right and left halves

Frontal plane

A perpendicular plane that divides the body into anterior and posterior portions

Transverse/cross-sectional plane

A horizontal plane that divides the body into superior and inferior portions

Oblique plane

Passes through the body at an angle other than 90^o

Cranial cavity

Formed by the cranial bones which contains the brain, continuous with the vertebral canal

Vertebral canal

Formed by the bones of the vertebral column which contains the spinal cord, continuous with the cranial cavity

Thoracic cavity

Formed by the ribs, the muscles of the chest, sternum, and the thoracic portion of the vertebral column. Within this cavity is the pericardial and mediastinum cavities

Pericardial cavity

A fluid-filled space that surrounds the heart (lined by pericardium) and two fluid filled spaces called pleural cavities (lined by pleura), one around each lung.

Mediastinum

Central part of the thoracic cavity, between the lungs and extending from the sternum to the vertebral column and from the first rib to the diaphragm. It contains all thoracic organs except the lungs

Diaphragm

Separates the thoracic cavity from the abdominopelvic cavity

Abdominopelvic cavity

Extends from the diaphragm to the groin and encircled by the abdominal muscular wall and the bones and muscles of the pelvis. Separated into the abdominal and pelvic cavities

Abdominal cavity

The superior portion (lined by peritoneum) and contains the stomach, spleen, liver, gall bladder, small intestine, and most of the large intestine

Pelvic cavity

The inferior portions and contains the urinary bladder, portions of the large intestine, and internal organs of the reproductive system

Viscera

Organs inside the thoracic and abdominopelvic cavities

Serous membranes

Covers the viscera and lines the walls of the thorax and abdomen. It has a parietal (lines the walls of the cavities) and visceral layer (lines the viscera) and forms a space in between that contains serous fluid

Orientation differences between bipeds and quadrupeds

In bipeds (humans)

Anterior = Ventral → toward the front (belly side).

Posterior = Dorsal → toward the back.

Superior = toward the head.

Inferior = toward the feet.

In quadrupeds

Ventral = belly side (facing the ground → inferior in anatomical position).

Dorsal = back side (facing upward → superior in anatomical position).

Anterior = toward the head (cranial).

Posterior = toward the tail (caudal).

Difference in sheep heart and human heart

In sheep, venous blood is drained via right ant. vena cava, left ant. vena cava, and post. vena cava causing the shape of the right atrium to be influenced and have three entrances

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A sheep heart from a ventral view

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The aorta of a sheep heart from a ventral view

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The left pulmonary artery of a sheep heart from a ventral view

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The pulmonary trunk of a sheep heart from a ventral view

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The left atrium of a sheep heart from a ventral view

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The left anterior vena cava of a sheep heart from a ventral view

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The left auricle of a sheep heart from a ventral view

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The left ventricle of a sheep heart from a ventral view

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The right ventricle of a sheep heart from a ventral view

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The right auricle of a sheep heart from a ventral view

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The ligamentum arteriosum of a sheep heart from a ventral view

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The brachiocephalic artery of a sheep heart from a ventral view

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The sheep heart from a dorsal view

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The brachiocephalic artery of a sheep heart from a dorsal view

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The right anterior vena cave of a sheep heart from a dorsal view

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The right atrium of a sheep heart from a dorsal view

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The posterior vena cava of a sheep heart from a dorsal view

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The right ventricle of a sheep heart from a dorsal view

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The left ventricle of a sheep heart from a dorsal view

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The left anterior vena cava of a sheep heart from a dorsal view

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The left atrium of a sheep heart from a dorsal view

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The pulmonary veins of a sheep heart from a dorsal view

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The left pulmonary artery of a sheep heart from a dorsal view

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The aorta of a sheep heart from a dorsal view