BIOL 320 Taylor Exam 2

Function of lymphatic system

- collect and filter tissue fluid from capillaries and return it to circulation

- Serves as a way to move white blood cells around

Tunica Intima

Inner layer of Artery/Vein

Endothelium

Subendothelial layer

Internal Elastic Lamina (Artery Only)

Tunica Media

- Smooth muscle and elastic fibers

- External elastic lamina (Artery Only)

Tunica Externa

- Collagen fibers

- Protection of vessels

- vasa vasorum

Vasa vasorum

Tiny blood vessels that supply the walls of large arteries and veins

Elastic artery tissue makeup

- Primary smooth muscle

- Elastic tissue

Muscular Artery tissue makeup

- Smooth muscle

- fibrous (Collagnous) Tissue

Arteriole tissue makeup

- Smooth muscle mostly

Capillary tissue makeup

- Endothelium only

Venule tissue makeup

- Endothelium

- Smooth muscle

- Fibrous Tissue

Vein tissue makeup

- mostly fibrous (Collagenous) tissue and smooth muscle

Elastic artery physical characteristics serve to

- Smooth out shock and even out flow

- They take pounding pulse of heartbeat and rebound back, resulting in consistent flow

- Does NOT Vasoconstrict

Muscular Artery characteristics

- Vasoconstrict to limit flow to inactive areas/tissues

- Responds to epinephrine

- Analogy of flushing toilet and person taking shower gets a rush of hot water

Arteriole characteristics

- Connect muscular arteries to capillary beds

- Vasoconstrict to further limit flow

- DO NOT cover great distances

Capillary Beds Purpose

- Serve as a passage of nutrients, gases, waste, hormones, etc.

- Arteries to veins

Precapillary Sphincters

Limit blood to capillary bed

Thoroughfare channels

Bypass capillary beds when capillary sphincter is closed

Pericytes

Help stabilize capillary walls and control permeability

Tissues without capillary beds

- Tendons/ligaments do not have good blood supply (Mostly why they take so long to heal)

- Cornea

3 Types of Capillary Wall Structure

Continuous, Fenestrated, and Sinusoidal

Continuous Capillary Wall

Very tight, transport of solutes

- Skin, muscle, brain

Fenestrated Capillary Wall

Fenestra with our without diaphragm

- pores

- Intestine, kidney, endocrine glands

Sinusoidal Capillary Wall

Solutes, fluid & cell transport, "loose and leaky"

- Large Gaps

- Liver, bone marrow, spleen

Veins have much larger relative ______________ vs. ______________ when compared to arteries

Internal diameter (lumen) vs. wall thickness

Valves purpose

Keep blood from flowing backwards

Vascular Anastomoses

brain, heart, abdominal organs, joints

Varicose veins and hemorrhoids both result from ______________.

Venous valve failure

Blood flow definition

Volume of blood through a defined area

- Defined area is vessel, organ, or system

Blood Pressure Definition

Force exerted on vessel wall by blood within

Resistance Definition

Opposition of flow: amount of friction encountered by blood

3 Resistance factors

Viscosity: inc viscosity, inc resistance

Blood Vessel length: inc length, inc resistance

Diameter: Inc Diameter, Dec resistance

2 types of blood flow

Laminar and turbulent

Laminar Blood Flow

- Streamlined

- Slower closest to wall, fastest in the center

Turbulent Flow

- Interrupted

- Runs into wall and bounces around due to rough surfaces

- This is why heart sounds when valve closes and why clots are an issue in people with vessel problems

Blood Flow Units

mL/min

Cardiac Output (CO) Definition

Blood flow through entire CVS

Blood Flow at rest is _____________ but ____________

Constant, but varies by need to individual organs

Poiseuille's Law

Blood flow is

- Inversely proportional to resistance, viscosity, vessel length

- Directly proportional to diameter and the change in pressure meaning the greater the difference, the faster the flow.

4 Mechanisms and 1 response of long term regulation of blood pressure

- Renin-angiotensin-aldosterone mechanism

- Vasopressin (ADH) mechanism

- Atrial natriuretic mechanism

- Fluid shift mechanism

- Stress-relaxation response

Stress-Relaxation Response

- Blood vessels dilate/constrict

- Tunica media adapts to change in blood volume

Why does BP Regulation matter

- Maintains blood through capillary beds

- Changes regional blood flow based on need

- Counteracts gravity

3 Factors of BP Regulation

Cardiac Output: Inc CO, Inc BP

Peripheral resistance inc, Inc BP

Blood Volume: inc BV, inc BP

Heart Rate (HR) control under normal situations

- Parasympathetic NS

- Cardio Inhibitory Center (CIC)

- Vagas Nerve X (M & S)

- Medulla

Stroke Volume (SV) control under normal conditions

via end-diastolic-volume (EDV)

HR Control under stressful conditions

- Sympathetic NS

- Cardioacclerator Center (CAC)

- Inc HR

SV Control under Stress

- Epinephrine/neural regulation increases

- Venous return increases

Short Term BP Controls

Neural controls and Vasomotor Center

Neural Controls (Short Term BP) Part 1/3

Specific demands

- When you stand up suddenly

- Recover pressure lost w/ hemorrhage

- Overcoming pooling in legs

Neural Controls (Short Term BP) Part 2/3

Maintenence of main arterial pressure via altering blood vessel diameter

Neural Controls (Short Term BP) Part 3/3

Operate via reflex arcs

- Receptor: Baroreceptor

- Integration center: Vasomotor Center

- Effector: Vascular smooth muscle

Location and Purpose of Vasomotor Center

- Sympathetic Neurons in the Medulla

- Regulate BV Diameter

Tone of the Vasomotor Center

Constant Low level of activity = Ready state

S-ANS Activity Increase results in

- Vasoconstriction

- Increased HR

- Increased BP

S-ANS Activity Decrease results in

P-ANS Resumes Control

- Decreased BP

Chemoreceptor Reflex Location

Aorta, Carotid

Chemoreceptor reflex measures

O2 and CO2

Chemoreceptor Reflex Stimuli and action

- Dec O2 and Inc CO2 Stimuli

- Activates vasomotor control

result of chemoreceptor reflex

Vasoconstriction -> Speed blood back to heart and lungs for oxygenation

- Coupled with Increased HR

2 Receptors of the VMC

Chemoreceptor and Baroreceptor

Baroreceptor reflex response to High BP

- Dec HR, Resistance, Contractility, Cardiac Output

Baroreceptor reflex response to low BP

- Inc HR, Resistance, Contractility, CO

Control Mechanism of Renal Long term BP Regulation

Blood Volume

Direct Pathway of Renal Long term BP Regulation

Overtime baroreceptor adapts to chronic high/low BP

- Results: High: Kidneys eliminate H2O, dec bld vol, dec BP

Low: Save water, inc bld vol, inc BP

Indirect Pathway of Renal Long Term BP Regulation

Low BP: Renin- Angiotensin mechanism

High BP: Beta-blockers (Vasodilators), Diuretics

Angiogenisis happens when

Short term autoregulation cannot meet tissue needs

- Common at High altitude

How does angiogenisis work

Increases #/size of vessels to region

2 Mechanisms the prevail when Skeletal muscle is at rest

Myogenic and general neural

During activity, Blood flow __________ to the metabolic activity of the _______. What controls override systemic controls?

Increases, Tissue

- Local Controls override systemic controls

Precapillary sphincters constrict when

- O2, nutrients & pH increase

- Metabolic byproducts & CO2 decrease

Precapillary Sphicters relax when

- O2, nutrients, and pH decrease

- Metabolic byproducts & CO2 increase

Blood Flow to the Brain is __________, as neurons are intolerant of _________.

Constant, Ischemia

Metabolic controls of the brain's BP vasodilate when

pH Decreases and CO2 Increases

Myogenic controls of the brain's BF do what when MAP decreases

Constrict Cerebral vessels

- Opposite when MAP increases

Atherosclerosis Definition and result

- Lipid deposit on vessel wall

- Turbulent flow, Increased resistance

Arteriosclerosis

- family of degenerative disorders

- Decreases elasticity of vessel wall

Systemic veins and venules make up _________ % of the CVS

60

Systemic arteries and arterioles make up ______% of the CVS

15

Pulmonary BV make up _______% of the CVS

12

The heart makes up ______% of the CVS

8

Capillaries make up ________% of the CVS

5

When standing, hydrostatic pressure caused by gravity _____________ BP below the heart and ____________ BP above the heart.

Increases, Decreases

Muscular movement ____________ Venous return

Improves

Extrinsic factors affecting BP

- Age

- Sex

- Weight

- Mood

- Race

- Posture

- Diet

- Physical Activity

Definition of Hypotension

Low BP, systolic less than 100 mm Hg

Orthostatic Hypotension Definition

temporary 'head rush' after suddenly standing

Chronic Hypotension definition

Result of poor nutrition

- Addison's disease or hypothyroid

Acute Hypotension is a sign of

Circulatory shock

Transient Hypertension is ___________, caused by __________

Normal; caused by fever, physical exertion or emotions

Chronic Hypertension can cause damage to

Vessels, baroreceptors, heart muscle, vascular organs

- Caused more commonly by heredity, stress, smoking

Circulatory Shock Definition

Blood volume low, cannot circulate normally

Result of circulatory shock

Inadequate blood flow to meet tissue needs

Hypovolemic shock

Large scale blood loss, vomit, diarrhea

Vascular Shock

extreme vasodilation

Cardiogenic shock

poor heart function

Obstructive shock

obstruction of blood flow

Anaphylactic shock

Massive histamine release (allergic rxn)

CNS Ischemic response

Elevation of BP in response to lack of BF to the Medulla Oblongata

Definition of and 2 Sources of lymph

- Water plus solutes

- Plasma and Cells

Difference between veins and lymphatic collecting vessels

- Collecting vessels have thinner walls and more internal valves

- Anastomose more frequently

Collecting lymphatic vessels travel with

superficial veins