Science 8: Unit B: Cells and Systems

1
Science 8 Unit B Cells and Systems

• Topic 6 Body Systems in Humans (pp. 146-153)
• Outcome Name and describe each of the five
  systems.

2
I. Digestive System

• Principal Organs Mouth, esophagus, liver,
  pancreas, stomach, small and large intestines.
• Major Role Digesting food into small particles
  which can be changed into energy by cells
  mitochondria.
• Needs Fulfilled Energy, growth, and eliminating
  wastes

3
II. Respiratory System

• Principal organs Larynx, trachea, bronchi,
  bronchioles, lungs, diaphragm, alveoli.
• Major role Taking in oxygen into the
  bloodstream, and expelling carbon dioxide. (gas
  exchange)
• Needs fulfilled Energy and eliminating wastes.

4
III. Circulatory System

• Principal Organs Heart, arteries, capillaries,
  veins.
• Major Role Transporting nutrients to cells and
  waste products away from cells.
• Needs Fulfilled Energy, eliminating wastes.
  (Vital for all needs really).

5
IV. Excretory System

• Principal Organs Kidneys, ureters, urethra,
  bladder.
• Major Role Filtering and expelling liquid wastes
  out of body.
• Needs Fulfilled Eliminating wastes.

6
V. Sensory Awareness System

• Principal Organs Brain- hypothalamus, sensory
  nerves, motor nerves, muscles, blood vessels,
  skin, hair. (Really a combination of systems
  working together, coordinated by the brain.)
• Major Role Adjusting bodys different systems to
  deal with outside environment.
• Needs Fulfilled Adapting to environment.

7
Circulatory System Overview

• I. Heart - the PUMP of the system.
• II. Arteries - Blood vessels which take blood
  AWAY from heart to rest of body. They are located
  deep inside your body so that they are safe from
  damage. Their thick, muscular walls keep pushing
  blood to all parts of the body.
• III. Capillaries - Tiny blood vessels, which are
  on cell thick. Nutrients (glucose, oxygen,
  protein, etc.) and wastes (carbon dioxide, urea,
  etc.) pass back and forth its walls through the
  process of DIFFUSION. Every cell in your body is
  in close contact with a capillary.

8
Circulatory System Overview

• IV. Veins - Blood vessels which take blood TO the
  heart. Blood in veins is low in nutrients and
  high in wastes so veins also travel to kidneys
  and lungs to get rid of waste products.
• Unlike arteries, veins do not have the muscular
  walls to push blood to the heart. Instead, veins
  have valves, which block blood from going
  backwards. Veins also move blood as they are
  moved by muscles. This is why cashiers and other
  people who have to stand still for long periods
  of time are at risk for damaged veins, and poor
  circulation (varicose veins)

9
Blood

• V. Blood - made up of four parts plasma, red
  blood cells, white blood cells, and platelets.
  The job of blood is to carry nutrients to cells
  while moving wastes away from cells.
• 1. Plasma - The liquid portion of blood. Actually
  yellowish in color, plasma is mostly water with
  the rest being proteins 55 of blood is plasma
• 2. Red Blood Cells - These disk-like cells carry
  the oxygen molecules that the cells need and the
  carbon dioxide molecules the cells need to get
  rid of. 40 of blood.

10
Blood Contd

• 3. White Blood Cells (WBC) - Help defend the body
  against infectious diseases and foreign
  particles. Also part of the immune system 4 of
  blood.
• 4. Platelets - Responsible for blood clotting
  anytime there is a wound. 1 of blood.

11
Excretory System Overview

• The Excretory System is the system responsible
  for filtering out and removing wastes from the
  body. This system has four main parts kidneys,
  ureters, a urethra, and a bladder.
• I. Kidneys - most important part of system. They
  filter out wastes from bloodstream and processes
  them into urine.

12
Excretory System Overview

• II. Ureters - Two tubes which move urine from
  kidneys to bladder. A small amount of urine is
  moved every 10 seconds.
• III. Bladder - Stores urine until limit is
  reached and nerve sensors are triggered. The urge
  to urinate begins here.

13
Excretory System Overview

• IV. Urethra - Tube that passes urine from bladder
  to exit point.

14
Sensory Awareness System

• Not really a body system on its own, but a group
  of responses coordinated by the brain and carried
  out by different parts of the muscular, nervous,
  digestive, and excretory systems.
• Your skin is fitted with sensory nerves all along
  its inside. There ar edifferents types of sensory
  nerves for pain, pressure, temperature, etc.

15
Sensory Awareness System

• If the temperature of your skin goes past certain
  limits, your brain takes action.
• If the sensory nerves signal that your skin is
  too cold, your brain sends signals to your
  muscles to start quivering, causing you to
  shiver. This rapid movement of muscles causes you
  to warm up your body temperature.

16
Sensory Awareness System

• If the sensory nerves signal that your skin is
  too hot, your brain sends signals to blood
  vessels near your skin to expand, releasing more
  heat to the outside. It also sends signals to
  other systems to save water and to excrete
  solutes. This causes you to sweat.

17
Sensory Awareness System

• Sometimes a stimulus needs such an immediate
  reaction that the signal doesnt even go to the
  brain. Instead, reflex reactions travel from a
  sensory nerve, go to the spinal cord and travel
  back down to a muscle nerve which performs the
  response. This is all automatic and does involve
  the brain at all. An example includes the
  knee-jerk reaction or placing your hand on a hot
  surface. The heat from the surface was the
  stimulus and the reflex reaction was you jerking
  your hand away.