IG

Grade 10 Bio Unit 1 The Human Circulatory system

LO.1 Describe the function of circulatory systems

The circulatory system is a system that transports nutrients in the blood throughout the body.

Substance Transported from. Transported To

  • Oxygen; Lungs. All living cells for respiration

  • Nutrients.; Small intestine Liver

  • Carbon dioxide: All cells, Lungs

  • Ammonia: All cells (breaks down Urea). Liver

  • Urea(Made from ammonia); Liver Kidneys (produce urine)

  • Hormones; Endocrine Glands Target cells

  • Heat: more active tissues. Less active tissues

Respiration is required for all living cells and is made from food and oxygen. As all living things in the body need energy, glucose and oxygen are transported throughout the body by diffusion.

A mass flow system

To supply oxygen, glucose, and other substances throughout the body, larger organisms require a transport system.

This system is called the blood system and is found in all vertebrate animals.

The mass flow systems carry large amounts of fluid to all organisms in a system of 4 parts.

  • A Medium - In this case is the fluid/ blood traveling throughout the body

  • A system of tubes - A place for the fluid to be carried from place to place. In the body are the arteries and capillaries

  • A pump - The heart that continues the supply of fluid to keep them moving throughout the tubes.

  • Sites of exchange - The place where materials are delivered by the blood entering the tissues needed. These are the capillaries.

Lo.2 describe the composition of human blood and the structure and functions of; red blood cells, white blood cells, platelets, and blood plasma.

Blood is the circulatory medium

The average adult has 5dm³ of blood in their body and some of these blood cells are suspended in a watery liquid called Plasma.

Formation of blood cells

Blood cells are first formed in the bone marrow of long bones such as the femur(thigh bone)

Types of blood cells.

Red blood cells (erythrocytes)

Appeareance

  • Function

Transports oxygen from the lungs to all respiring cells. It also prepares carbon dioxide frpm all respiring tissues to the lungs.

  • How the structure is suited to its function

    Contains haemoglobin, an iron-containing pigment that picks up oxygen in the lungs and then drops it off in the tissues.

    has no nucleus, creating more space for haemoglobin

The cells are extremely and small, making it easy to pass through the capillaries

  1. White blood cells (phagocytes)

Appearance

Function:

removes microorganisms that may cause disease and infection in the body by engulfing them

How the structure is suited to their function:

An irregularly shaped nucleus allows cells to squeeze through gaps in the walls of the capillaries.

Enzymes in the cytoplasm digest microorganisms once engulfed.

Sensitive cell surface membrane can detect microorganisms

  1. White blood cells (lymphocytes)

    Appearance:

    Function:

    Produce an antibody-protein to help defend against disease.

    How the structure is suited to its function:

    A large nucleus containing many copies of genes for the control of antibody proteins

  2. Platelets

    appearance:

    Function:

    blood clots

Lo.3 Describe the structure and function of the arteries, capillaries, and veins.

Arteries

function:

To transport blood at high pressure from the heart to the tissues of the body and lungs.

structure:

  • narrow lumen for maintaining high pressure of blood flow

  • A thick, elastic wall of muscles that prevent rupturing under high blood pressure and allow elastic recoil.

veins

function;

to carry(collect) blood from tissues at a low blood pressure to the heart.

structure

  • Wide/ large lumen, which helps with being more effective at returning blood to the heart

  • contains fewer muscles and elastic fibers for the blood to flow more slowly

  • contains valves which prevent backflow

valves

As blood is moving slowly in the veins, it makes it difficult to move against the downflow force of gravity.

The veins pass by skeletal muscle groups, which help squeeze the vein when contracting and keep blood flow.

capillaries

Structure:

  • extremely small and only allows 1 red blood cell at a time

  • made of a single layer of cells to minimize distance of diffusions( cuz it moves so slowly)

function

  • To exchange materials between cells in tissues and blood, traveling at low pressure

  • The branching of arteries turns into capillaries, causing blood to move slowly as all cells are near a blood supply.

  • after material exchange is occurs, capillaries pool into small veins which join up into larger veins and return blood to the heart

LO. 4 Describe the structure of the heart

when looking at a diagram of a heart. The left side is always on the side where it would be if a human were facing towards you. meaning backwards of the way we are standing or sitting

, the human heart is a 4 chambered organ made up of 2 atria and 2 ventricles.

The atria act as reservoirs, collecting blood entering the heart in veins, and are where the oxygenated blood flows around the body

The ventricles act as pumps, expelling(pushing) deoxygenated blood from the heart at high pressure in the arteries.