Introduction

3 Major types of blood vessels Body Body RA RA RV RV Lungs Lungs LA LA LV LV Boby Boby 1.Arteries 2.Capillaries 3.Veins Arteries carry blood away from the heart -”branch,” “diverge” or “fork” Veins carry blood toward the heart -”join”, “merge,” “converge”

General characteristics of vessels Three layers (except for the smallest) Three layers (except for the smallest) 1. Tunica intima - AKA intima 2. Tunica media – smooth muscle 3. Tunica externa - AKA adventitia Lumen is the central blood filled space Lumen is the central blood filled space

Intima is endothelium (simple squamous epithelium) Intima is endothelium (simple squamous epithelium) Tunica media: layers of circular smooth muscles Tunica media: layers of circular smooth muscles Smooth muscle contraction: vasoconstriction Smooth muscle relaxation: vasodilation

Veins Pressure has been lowered so capillaries can tolerate Pressure has been lowered so capillaries can tolerate With lower pressure, walls (of veins) can be thinner With lower pressure, walls (of veins) can be thinner From smallest to large: From smallest to large: Capillaries to postcapillary venules to venules to veins Veins are larger than arteries, plus Veins are larger than arteries, plus Tunica externa is thicker Tunica externa is thicker There is less elastin There is less elastin

Special features of veins Valves Valves Prevent backflow Prevent backflow Most abundant in legs (where blood has to travel against gravity) Most abundant in legs (where blood has to travel against gravity) Muscular contraction Muscular contraction Aids the return of blood to heart in conjunction with valves Aids the return of blood to heart in conjunction with valves Mechanical issues… (really good to know)

Systemic Circulation Oxygenated blood to body Oxygenated blood to body Leaves LV through Ascending Aorta Leaves LV through Ascending Aorta Only branches are the 2 coronary arteries to the heart Only branches are the 2 coronary arteries to the heart Aortic Arch has three arteries branching from it: Aortic Arch has three arteries branching from it: 1. Brachiocephalic trunk, has 2 branches: Right common carotid a. Right common carotid a. Right subclavian a. Right subclavian a. 2. Left common carotid a. 3. Left subclavian a.

Descending aorta Descending aorta Thoracic aorta Thoracic aorta at T12 becomes abdominal aorta at T12 becomes abdominal aorta Abdominal aorta Abdominal aorta ends at L4 branching into: ends at L4 branching into: R & L common iliac arteries R & L common iliac arteries

Angiogram

Systemic Veins 3 major vessels enter Right Atrium: 3 major vessels enter Right Atrium: SVC (superior vena cava) SVC (superior vena cava) IVC (inferior vena cava) IVC (inferior vena cava) Coronary sinus Coronary sinus Many veins are very superficial (unlike arteries) Many veins are very superficial (unlike arteries)

Vein overview Note that unlike the arteries, the veins have a brachiocephalic on the right and left sides

Nervous system

Nervous System Nervous tissue consists of two main cell types: neurons (nerve cells) and neuroglia (glial cells), which support the neurons. Nervous tissue consists of two main cell types: neurons (nerve cells) and neuroglia (glial cells), which support the neurons.

The nervous system is divided Structurally into the central nervous system (CNS) and peripheral nervous system (PNS). Structurally into the central nervous system (CNS) and peripheral nervous system (PNS). Functionally into the somatic nervous system (SNS) and autonomic nervous system (ANS).

Cranial Nerves There are 12 pairs of cranial nerves that leave the brain and pass through foramina in the skull. There are 12 pairs of cranial nerves that leave the brain and pass through foramina in the skull. All the nerves are distributed in the head and neck except the Xth (vagus), which also supplies structures in the thorax and abdomen. All the nerves are distributed in the head and neck except the Xth (vagus), which also supplies structures in the thorax and abdomen.

Spinal Nerves A total of 31 pairs of spinal nerves leave the spinal cord and pass through intervertebral foramina in the vertebral column. A total of 31 pairs of spinal nerves leave the spinal cord and pass through intervertebral foramina in the vertebral column. 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal. 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal.

Spinal nerve(anterior and posterior rami) On emerging from the foramen, the spinal nerve divides into a large anterior ramus and a smaller posterior ramus. On emerging from the foramen, the spinal nerve divides into a large anterior ramus and a smaller posterior ramus. Posterior ramus passes posteriorly around the vertebral column to supply the muscles and skin of the back. Posterior ramus passes posteriorly around the vertebral column to supply the muscles and skin of the back. Anterior ramus continues anteriorly to supply the muscles and skin over the anterolateral body wall and all the muscles and skin of the limbs. Anterior ramus continues anteriorly to supply the muscles and skin over the anterolateral body wall and all the muscles and skin of the limbs.

Spinal nerve

Plexuses A nerve plexus is a network of intersecting nerves. A nerve plexus is a network of intersecting nerves.nerves Except for the ventral rami of Th2-Th12 nerves. Except for the ventral rami of Th2-Th12 nerves. At the root of the limbs, the anterior rami join one another to form complicated nerve plexuses. At the root of the limbs, the anterior rami join one another to form complicated nerve plexuses. The cervical and brachial plexuses are found at the root of the upper limbs, and the lumbar and sacral plexuses are found at the root of the lower limbs. The cervical and brachial plexuses are found at the root of the upper limbs, and the lumbar and sacral plexuses are found at the root of the lower limbs.

Autonomic Nervous System 2 divisions: 2 divisions: Sympathetic Sympathetic “Fight or flight” “Fight or flight” “E” division “E” division Exercise, excitement, emergency, and embarrassment Exercise, excitement, emergency, and embarrassment Parasympathetic Parasympathetic “Rest and digest” “Rest and digest” “D” division “D” division Digestion, defecation, and diuresis Digestion, defecation, and diuresis