{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

CIRCULATORY copy - CIRCULATORY Circulatory System =...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
CIRCULATORY Circulatory System = functions as transport system of body, picks up oxygen from respiratory structures, nutrients from digestive tract, hormones from endocrine glands, and other needed materials such as antibodies, transports them to tissues, and then returns CO 2 , nitrogenous waste, and other excess substances in the interstitial fluid to site of removal from body Important Circulatory System Roles (3): 1. Thermoregulation = transport of metabolic heat through body o Evolved mechanisms – shunt blood toward/away from body parts that need to be heated/cooled 2. Coagulants (in blood) – necessary to stop bleeding at injured sites 3. Transport of antibodies (and other substances) – important to protect body from pathogens 2 Divisions of Circulatory System: Blood-Vascular System and Lymphatic System Blood-Vascular system = includes components of blood, vessels, heart o Blood – composed of liquid plasma (90% water, plasma proteins – ex. Albumin, Globulin), and number of cell types 3 categories of blood cells: 1. Erythrocytes (red) – nucleated (most vertebrates), non-nucleated (vertebrates) – contain hemoglobin – binds with oxygen transports to tissue 2. Leukocytes (white) – main function = defense of body by engulfing/ destroying foreign particles, releasing histamine to aid in inflammatory reactions, initiating immune responses 3. Thrombocytes (platelets) – circulating cell fragments, initiate blood clotting o Vertebrates = closed circulatory system, blood confined in blood vessels 2 types of blood vessels: 1. Arteries = carry blood from heart to capillary networks in tissues, high oxygen content blood (except pulmonary) o Walls relatively thick – very muscular layer, elastic – allow for expansion when blood pumped into, recoil – keep blood flowing o Branch into smaller Arterioles = large amount smooth muscle Capillaries = wall only consisting of endothelium, gas exchange here between blood, interstitial fluid Diameter of vessels decrease – vessel number increased combine cross-sectional area increased (770 times aorta) Flow rate greatly decreased, more time available for diffusion of materials between blood, interstitial fluid 2. Veins = return blood back to heart, low oxygen content blood (except
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
pulmonary) o Capillaries Venules – decreasing in combined surface area, flow rate increases Veins – thinner walls, larger than arteries Smooth muscle lining arteries/veins – important role in blood distribution in body o Autonomic nervous system/hormone control – smooth muscle vessel lining contract or relax depending on signal type Contract smooth muscle shortens vessel diameter decreases - Vasoconstriction diameter decrease + resistance increase = blood diverted through other vessels Relax diameter increases response = Vasodilatation diameter increase + pressure decrease = flow through vessel increases Ventricular contraction blood pushed into aorta aorta stretches under pressure
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern