33: Circulation

Components of circulatory systems

blood, heart, blood vessels

Blood

transport gasses, nutrients and cellular waste

heart

pumps blood

blood vessels

arteries, veins, capillaries

arteries

carry blood away from the heart

veins

carry blood to the heart

Capillaries

link arteries and veins, material exchange through walls

open circulatory system

organs bathe directly in blood

-tissues bathe by hemolph in hemocoel

-less energy used

-sedentary animals

- blood doesn't carry oxygen to tissues

- gas exchange goes through trachea tubes

hemocoel

body cavity where tissues are bathed in hemolymoh

hemolymph

fluid that functions as blood

closed circulatory system

blood confined in blood vessels

-higher pressure

-blood adusts in vessels

- all vertabres and some in vertabrets

system supports all other body systems

circulatory system supports gas exchange, nutrient distroubtion, water transport, horomone transport, tempature regulation, wound healing, imune defense

atrium

collects blood

ventricle

circulates blood

Two chamered hearts

-fish

- one atrium, one ventricle

- low blood pressure and needs water buyancy to live

- ventricle,gill (for O2),body, atrium

3 chambered heart

-amphibias

-2 atrium, 1 ventricle

-double circulation: pulmonary ad systemic

-oxygenated and deoxygenated bood mix

pulmonary circuit

blood travels to lungs for gas exchange

systemic circut

blood travels between heart and the rest of the body

4 chambered heart

-crocodiles, birds, mammals

-right and left to prevent blood mixing

-right is oxygen poor, goes to lungs

-left is oxygen rich, goes to aorta

- endothermy, high metabolic rate

more muscular human heart chamber

left because it pumps blood through whole systemic unity

Valves

ensure one way blood flow

Artioventricular valves

-stop backflow into artia,

-between artoa and ventricles

semilunar valves

between ventricles and arteries, prevent backflow into arteries

cardiac muscles

interlaced dics with memberane lined channels

-electrical signals spread rapidly

Cardiac cycle

Sequence of events in one heartbeat.

1. both atria contract and fill venrticls with blood

2. both ventricls contract and push blood into arteries

3. entire heart relazes then refill

systolic blood pressure

-higher

-pressure in arteries when ventricle contracts

Diastole pressure

low pressure

-prssure in arteries when heart rests

Healthy blood pressure range

120/80 or below

Hypertension

higher than normal blood pressure(120/80)

pacemaker

built in electricalsystem that controls the heart rhythm

sinoatrial (SA) node

right atrium, initiates electrecal signal

Atrial Node

signal spreads through both atria making them contract

artioventricular node

revieves and sligthly delays signal

atria finish emptying into ventricle before it contracts

AV bundle and parkinje fibers

conduct signal rapidly at the base of the ventricles

triggers cintraction pushing blood up and out of heart

parasympathetic nervous system

slows heart rate during rest

sympathetic nervous system

Increases heart rate and contractility.

Adrenile gland

releases adernaline sympathizes response

Blood composition

plasma, red blood cells, white blood cells, platelets

Plasma

liquid part of blood

plasma proteins

albumins, globulins, fibrinogen

albumin

osmotic strength to prevent blood loss from cappilaries

golbumins

antibodies for immune defense

Fibrinogen

critical for blood clottig

red blood cells (erythrocytes)

-transport oxygen from lungs to tissues,

-hemoglobin

Hemoglobin

iorn coating protien binds 4 o2 molecules

Negative feedback for red blood cells

1. sensor: kidney detects low oxygen levels

2. effector: kidney relase erythrpoiten horomone

3. Action: erythrpoiten stims bone marrow to produce more blood cells

recyclyed iorn

iorn from dead cells is sent back to the bone marrow

white blood cells (leukocytes)

defend body from disease

can crawl to infection sight ad change shape

Blood Clots

fragments of large cells

clotting cascade

1.Platelet finds exposed collagen of damaged vessel

2.chemical reaction turns prothrombin into thrombin (enzymes)

3. thombrin turns fibrogen into fibrin strands

4. fibrin webs trap celss pushing wound eges together

Hemophilia

genetic lack of clotting

blood vessel hierarchy

heart, arteries, arterioles, capillaries, venules, veins, heart

endothelium

innermost lining of blood vessels

larger vesssels

smooth muscle inside with outer connective tissue

capilaries

endothelium to facilitate exchange

Arteries

carry blood away from the heart, thicker walls

Arterioles

smallest arteries

exchange site

cappilaries

diffusion, spaces/ crevices, vesicles

diffusion

gasses, water, liquid solulbe substances move through memberane

spaces/crevices

water soulble nutrients move through gaps between cells

vesicles

moves small proteins

Percapillary spincter

ring of muscle

veins and venules

thin walls, one way flow

Skeletal Muscle Pump

pumping effect of contracting skeletal muscles on blood flow through underlying vessels

lymphatic system

interfaces with circulatory system

-fluid recovery, fat transport, blood clenseaing, immune defense

lymphatic capillaries

dead end, stretch throughout whole body

lymph

watery fluid

large vesseles

one way valves, resemble veins

lacteals

specialized lymphatic capillaries in small intestine

bone marrow

A soft tissue inside the bone that produces blood cells, sit of lymphovyte production

thymus

site of lymposyte growth

tonsils

tissue patches in pharynx that gaurd against pathogens

lymph nodes

swelling along vessels, filterlymph through white blood cells

Spleen

filters blood past macropages and lymphcytes, break down red blood cell, stores blood for emergencies