Human Anatomy and Physiology Quiz

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Questions and Answers

What is the correct order of blood flow from the cranial vena cava back to the aorta?

Cranial vena cava → right atrium → right ventricle → pulmonary artery (correct)

Cranial vena cava → right atrium → left atrium → thoracic duct

Cranial vena cava → left atrium → pulmonary trunk → aortic valve

Cranial vena cava → right atrium → left ventricle → aortic arch

Which lymphatic structure is known to terminate in the mediastinal venous system?

Cisterna chyli

Pulmonary vein

Thoracic duct (correct)

Brachiocephalic vein

What is the first arterial branch off the aortic arch?

Left subclavian artery

Brachiocephalic trunk (correct)

Common carotid artery

Right coronary artery

Which vein is responsible for transporting deoxygenated blood from the gastrointestinal tract to the liver?

Portal vein Signup and view all the answers

Where is the celiac artery specifically located?

Below the cranial mesenteric artery Signup and view all the answers

What is the primary function of the capillary beds mentioned in the content?

To facilitate the arterial-venous exchange Signup and view all the answers

Which heart valve is located between the left atrium and the left ventricle?

Left atrioventricular valve Signup and view all the answers

Which of the following vessels delivers blood to the hind limbs?

External iliac artery Signup and view all the answers

Which condition is characterized by dribbling from the umbilicus and a high susceptibility to urinary tract infections?

Patent urachus Signup and view all the answers

What is the primary nerve responsible for innervating the diaphragm?

Phrenic nerve Signup and view all the answers

Which part of the autonomic nervous system is mainly responsible for 'rest and digest' activities?

Parasympathetic nervous system Signup and view all the answers

Which sympathetic structure is associated with the functioning of the thoracic limb?

Cervicothoracic ganglion Signup and view all the answers

What effect does sympathetic activation have on the heart?

Increases heart rate Signup and view all the answers

Which of the following spinal nerves contribute to the formation of the brachial plexus?

C5, C6, C7, C8, T1, T2 Signup and view all the answers

Which of the following is a characteristic symptom of patent ductus arteriosus?

Washing machine murmur Signup and view all the answers

Which of the following nerves is part of the parasympathetic autonomic nervous system?

Vagus nerve Signup and view all the answers

Which nerve is responsible for innervating the caudomedial antebrachial muscles?

Median n. Signup and view all the answers

What would likely occur if the radial nerve were damaged?

Loss of digit extension Signup and view all the answers

Which of the following branches off the left subclavian artery is the first to arise?

Vertebral Signup and view all the answers

The musculocutaneous nerve is responsible for loss of function in which area?

Medial forelimb sensitivity Signup and view all the answers

Which nerve is primarily responsible for the sensation loss on the palmar paw?

Median n. Signup and view all the answers

What is the function of the axillary nerve?

Impaired shoulder flexion Signup and view all the answers

Which nerve supplies the caudal joint area and the abaxial aspect of digit 5?

Ulnar n. Signup and view all the answers

When does the subclavian artery become the primary supply for the thoracic limb?

After passing the first rib Signup and view all the answers

What is the primary arterial supply change from the left subclavian artery at the 1st rib?

Left subclavian → axillary artery Signup and view all the answers

Which artery is identified at the axillary to brachial artery transition?

Cranial circumflex humoral artery Signup and view all the answers

What is the clinical significance of the cephalic vein?

It provides multiple routes back to the heart. Signup and view all the answers

Which lymph node drains both the thoracic limb and thoracic wall?

Axillary lymph node Signup and view all the answers

What does the term 'orad' refer to in a clinical context?

Towards the mouth Signup and view all the answers

What is the main function of the hepatic portal system?

To filter toxic substances before returning blood to the heart Signup and view all the answers

Which veins form the initial portal vein in the hepatic portal system?

Cranial mesenteric vein and caudal mesenteric vein Signup and view all the answers

Where does bile from the gallbladder enter the digestive system?

Major duodenal papilla Signup and view all the answers

What anatomical feature differentiates the ileum from the jejunum?

Anti-mesenteric iliac artery's endpoint Signup and view all the answers

Which structure is associated with the major duodenal papilla?

Bile duct Signup and view all the answers

What would be the consequence if venous blood from the digestive organs drained directly into the caudal vena cava?

Toxins would enter circulation unchecked Signup and view all the answers

What role do the two capillary beds in the hepatic portal system play?

They allow for nutrient absorption and toxin filtration Signup and view all the answers

Where does the bile duct drain bile into the digestive system?

Major duodenal papilla Signup and view all the answers

Study Notes

Blood Flow Through Heart and Lungs

Blood flow begins in the cranial vena cava, entering the right atrium.
The right atrioventricular valve directs blood into the right ventricle.
The pulmonary valve then pushes blood through the pulmonary trunk, into the pulmonary artery.
The pulmonary artery carries blood to the lungs for oxygenation.
Oxygenated blood returns to the heart via the pulmonary vein, entering the left atrium.
It then passes through the left atrioventricular valve and enters the left ventricle.
The aortic valve opens, sending oxygenated blood through the aortic arch and into the aorta, which supplies the body.

Lymphatic Structures of the Thoracic Cavity

The thoracic duct is a continuation of the cisterna chyli, located near the lumbar vertebrae.
It travels upward, becomes the thoracic duct once it reaches the diaphragmatic crura, and terminates in the mediastinal venous system.

Major Arterial Branching Pattern from Heart to Distal Aorta

On Heart
- The aorta branches into the right and left coronary arteries, which further branch into the paraconal interventricular, circumflex, and subsinuousal interventricular arteries.
- The aortic arch branches into the brachiocephalic trunk (first branch off the arch), which subsequently divides into the right common carotid (first branch off the brachiocephalic trunk) and the right subclavian artery (parallel to the right carotid).
- The left subclavian artery branches off after the brachiocephalic trunk.
Distal Aorta in Cavity
- Celiac artery - branches off the aorta to supply the stomach and liver.
- Cranial mesenteric artery - located below the celiac artery, supplying the intestines.
- Caudal mesenteric artery - located much below the cranial mesenteric artery, supplying the intestines.
- External iliac arteries - the initial pair of parallel branches at the bottom of the aorta, supplying the hind limbs.
- Internal iliac arteries - the second pair of parallel branches, supplying the pelvic viscera.
Capillary Beds - found in the stomach, spleen, GI tract, and liver. These capillary beds facilitate exchange between the venous and arterial systems before blood reaches the heart.

Venous Return Via the Portal System Back to the Heart

The portal system acts as a filtering system, removing deoxygenated blood from the GI tract and returning it to the heart.
It begins where the cranial and caudal mesenteric veins join.
Portal vein tributaries - these include the gastroduodenal vein, splenic vein, and right gastric vein.
The portal vein enters the liver, exits via hepatic veins, and joins the caudal vena cava.

Four Heart Valves

The four heart valves can be best heard via auscultation (use of a stethoscope) at specific locations:
- Aortic Valve - best heard on the left side of the chest, between the 4th and 5th intercostal space, just above the edge of the sternum.
- Pulmonary Valve - best heard on the left side of the chest, between the 3rd and 4th intercostal space, just above the edge of the sternum.
- Mitral Valve- heard on the left side of the chest, between the 5th and 6th intercostal space, just below the edge of the sternum.
- Tricuspid Valve - heard on the left side of the chest, between the 4th and 5th intercostal space, near the sternum.

Clinical Significance of Specific Conditions

Patent urachus - dribbling from the umbilicus, high susceptibility to urinary tract infections (UTIs).
Patent ductus arteriosus - a washing machine murmur sound during auscultation, ventricular hypertrophy.
Patent foramen ovale - murmur sound during auscultation, right ventricular hypertrophy.

CNS, PNS, and ANS

CNS (Central Nervous System) - consists of the brain (cerebrum, brainstem, cerebellum) and spinal cord, and is enclosed within bones.
PNS (Peripheral Nervous System) - consists of cranial nerves and spinal nerves, extending throughout the body after the neck.
ANS (Autonomic Nervous System) - responsible for automatic bodily functions, divided into the sympathetic (fight or flight) and parasympathetic (rest and digest) systems.

Sympathetic and Parasympathetic Nerves

Parasympathetic - associated with cranial nerves 3, 7, 9, and 10, the vagus nerve, and the pelvic nerve (S1-S3). Other associated structures include the vagosumpathetic trunk, laryngeal nerve, and dorsal/ventral vagal branches/trunks.
Sympathetic - associated with the cervicothoracic ganglion, ansa subclavia, vertebral nerve, middle cervical ganglion, sympathetic trunk, vagosympathetic trunk, splanchnic nerves (major, minor, lumbar), abdominal plexus, hypogastric plexus, celiocomesenteric ganglion, and caudal mesenteric ganglion.

Phrenic Nerve

Origin: C5, 6, 7 (cervical plexus).
Course: travels caudally towards the diaphragm.
Function: innervates the diaphragm (responsible for hiccups).

Sympathetic vs. Parasympathetic Effects on Organs and Senses

Iris: dilates (sympathetic), constricts (parasympathetic).
Heart: increases rate (sympathetic), decreases rate (parasympathetic).
GI Tract: reduces peristalsis (sympathetic), increases motility (parasympathetic).

Brachial Plexus

Plexus: A network of nerves that converge and diverge to form other nerves.
The brachial plexus is crucial in dogs, giving rise to thoracic limb nerves.
It is formed by spinal nerves C6, 7, 8, and T1-2.

The Big Six Nerves of the Brachial Plexus

1. Suprascapular Nerve: originates from C6, 7 and innervates the lateral muscles of the shoulder.
2. Musculocutaneous Nerve: originates from C6, 7, 8 and innervates the medial shoulder muscles and cranial brachium muscles.
3. Axillary Nerve: originates as a branch from C7, 8 and innervates the lateral and medial muscles of the shoulder.
4. Median Nerve: originates from a common trunk formed by C8, T1, 2 and innervates the caudal medial antebrachial muscles.
5. Ulnar Nerve: originates from a common trunk formed by C8, T1, 2 and innervates the caudal medial antebrachial muscles.
6. Radial Nerve: originates from C7, 8, T1, 2 and innervates the caudal muscles of the brachium and the craniolateral antebrachial muscles. The radial nerve is the largest nerve bundle in the brachial plexus.

Loss of Function Due to Nerve Damage

1. Suprascapular Nerve: "Shoulder sweeny" - muscle atrophy in the shoulder, noticeable by the highly palpable scapula.
2. Musculocutaneous Nerve: loss of elbow flexion and decreased medial forelimb sensitivity.
3. Axillary Nerve: impaired shoulder flexion, loss of sensation on the lateral shoulder.
4. Median Nerve: weakened flexion and pronation of the carpus (wrist), loss of sensation on the palmar paw.
5. Ulnar Nerve: weakened flexion of the carpus and digits, loss of sensation on the lateral paw.
6. Radial Nerve: loss of elbow, carpus, and digit extension, difficulty bearing weight, loss of sensation on the dorsal paw..

Cutaneous Nerves of the Thoracic Limb

1. Radial Nerve → Radial nerve, lateral cutaneous antebrachial nerve: sensory zone covers the middle of the dorsal paw, cranial and lateral antebrachium.
2. Axillary Nerve → lateral cutaneous brachial nerve: sensory zone covers the lateral brachium.
3. Median Nerve → Median nerve: sensory zone covers the middle of the palmar paw.
4. Ulnar Nerve → caudal cutaneous antebrachial nerve: sensory zone covers the caudal cubital joint to the antebrachium, abaxial digit 5.
5. Musculocutaneous Nerve → medial cutaneous antebrachial nerve: sensory zone covers the medial antebrachium.

Subclavian Artery and Its Branches

Left Subclavian Artery - branches off after the brachiocephalic trunk.
Vertebral Artery - first branch off the subclavian artery.
Costocervical Trunk - second branch off the subclavian artery, on the same side as the vertebral artery.
Superficial Cervical Artery and Internal Thoracic Artery - the next branches, located at 180 degrees from each other.
Primary Supply to the Thoracic Limb - the subclavian artery becomes the primary supply after passing the first rib and transforming into the axillary artery.

Arterial Supply of the Thoracic Limb

At the 1st Rib: the left subclavian artery becomes the axillary artery.
At the Cranial Circumflex Humoral Artery (humoral Joint): the axillary artery becomes the brachial artery.
At the Common Interosseous Artery (cubital Joint): the brachial artery becomes the median artery.
Left Subclavian Artery (1st rib) → Axillary Artery (cranial circumflex humoral artery) → Brachial Artery (common interosseous artery) → Median Artery

Venous Return of the Thoracic Limb

Cephalic Vein: Commonly used for blood draws, and can return blood to the heart through several routes:
- Omobrachial vein
- Axillary brachial vein
- Median cubital vein
- Axillary vein (all connect to the cranial vena cava).
Clinical Significance: due to its accessibility and ability to drain the thoracic limb, the cephalic vein is commonly used for blood draws and for introducing IV fluids.

Superficial Cervical and Axillary Lymph Nodes

Superficial Cervical Lymph Nodes - drain the head, neck, and part of the thoracic limb.
Axillary Lymph Nodes - drain the thoracic limb and thoracic wall.
Additional Lymph Nodes:
- Tracheobronchial Lymph Nodes - located at the bifurcation (branching point) of the principal bronchi.
- Cranial Mediastinal Lymph Nodes - found above the trachea, cranial to the heart, in the mediastinal region.
- Cranial Sternal Lymph Nodes - located on the cranial sternum.
Connection: The lymphatics system is interconnected throughout the body, allowing efficient drainage and defense against infections.

Alimentary System Terms

Orad - Towards the mouth
Aborad - Away from the mouth

Mesothelial Fold Transformation

The abdominal mesothelial fold connects to the primitive endoderm.
This connection transforms to create final structures in neonates, including:
- Mesentery - the attachment for the intestines to the dorsal body wall.
- Omentum - a sheet-like extension of the peritoneum that covers the abdominal organs.
Location: The mesentery is typically found in the cranial aspect of the left quadrant in the abdominal cavity.

Bile Flow

Free bile exists within the gall bladder.
Drainage occurs through the cystic duct.
Bile flows through the hepatic ducts (from each liver lobe) and into the cystic duct.
The cystic duct becomes the bile duct at the last hepatic duct.
Bile Duct - empties into the major duodenal papilla and into the duodenum.

Duodenal Papillae

Major Duodenal Papilla - located in the descending duodenum, closer to the cranial flexure. It receives fluid from the pancreatic duct and bile duct.
Minor Duodenal Papilla - located in the descending duodenum, closer to the caudal flexure. It receives fluid from the accessory pancreatic duct.

Hepatic Portal System

The hepatic portal system is crucial for filtering blood before it returns to the heart for oxygenation.
It processes both nutrients and toxins.
Initial Portal Vein - formed by the cranial mesenteric vein (blood from the small intestine, large intestine, and pancreas) and the caudal mesenteric vein (blood from the descending colon and rectum).
Capillary Beds:
- First Capillary Bed: Found in digestive organs, where blood absorbs nutrients and toxins.
- Second Capillary Bed: Located in the liver, where toxic blood is filtered before entering the vena cava.
Reason for Not Draining into the Caudal Vena Cava: Blood from the GI tract carries many toxins, and it is not safe for this toxic blood to enter the heart without being filtered.
Clinical Significance: understanding the portal system is vital for diagnosing and treating conditions involving the liver and digestive system.

Ileum and Jejunum

Visual Differentiation: The anti-mesenteric iliac artery marks the transition from the jejunum to the ileum. The jejunum lies cranial to the artery, while the ileum lies caudal to it.

Clinical Importance of Structures

Surgical Procedures: Knowledge of the vasculature and related structures is essential for successful surgical procedures, minimizing blood loss, and ensuring adequate tissue perfusion.

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Description

Test your knowledge on human anatomy and physiology with this quiz. Questions cover topics such as blood flow, heart valves, arteries, and the autonomic nervous system. Perfect for students studying these essential concepts.