Body Systems

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Body Systems

• Our bodies are made up of several systems that
  work together to perform certain functions and
  tasks in order to maintain homeostasis. Although
  each system has its own task or task to
  accomplish, all systems employ other systems.
• Example the muscular system, nervous system and
  the skeletal system work together during movement.

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Levels of organization

• Cells
• Tissue
• Organs
• Organ systems
• Organism

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Digestive System

• the function of the digestive system is to
  convert food into simple molecules that can be
  absorbed and used by cells in the body.

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1. Path of food through the digestive tract

• a. Mouth mechanical breakdown of food with
  teeth and chemical breakdown of food via saliva.
  Food is broken down into a pasty substance called
  bolus.
• b. Esophagus bolus is transported form the
  mouth to the stomach via the esophagus. To get
  the food to the stomach, the esophagus contracts
  rhythmically. (peristalsis)
• c. Stomach combination of mechanical digestion
  by grinding, and chemical digestion. The stomach
  has a ribbed lining to grind food, and secretes
  hydrochloric acid to break down food.
• d. Small intestine most digestion and nutrient
  absorption occurs here. Nutrients are absorbed
  and delivered to the blood stream
• e. Large intestine removes water from
  undigested material
• f. Pancreas produces digestive enzymes
• g. Liver produces bile to break down fat
• h. Gall bladder stores excess bile

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The Excretory System

• The function of the excretory system is to
  maintain homeostasis.

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Excretory Organs

• Lungs excrete carbon dioxide
• Skin excretes excess water and salt
• Liver converts nitrogen wastes into urea
• Kidneys main excretory organ of the excretory
  system
• Remove waste products from the blood
• Maintain blood pH
• Regulate water content of blood
• Filtered waste travels through the ureters
• Waste is stored in the urinary bladder

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The Circulatory System

• means of communication and transport throughout
  the body

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Components of the Circulatory System

• a. Heart pumps blood
• b. Arteries carry oxygen rich blood away from
  the heart, to organs. Lined with smooth muscle to
  aid the heart
• c. Capillaries smallest vessels that are one
  cell thick. Allow nutrients to diffuse from blood
  to the tissue. Carries away waste products to the
  excretory organs
• d. Veins carry deoxygenated blood from the
  capillaries to the heart

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Functions of the circulatory system

• a. Transport oxygen to the organs
• Oxygen binds with hemoglobin on the red blood
  cell
• b. transport nutrients from the digestive tract
  to the cells
• c. transport waste from the cells to excretory
  organs
• d. transport heat energy
• e. transport hormones
• f. transport white blood cells
• g. transport platelets to clot broken vessels

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Blood is a mixture
11
The Respiratory System

• supplies oxygen to the blood stream and takes
  away carbon dioxide

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1. Path of an oxygen molecule through the
respiratory tract

• a. Nasal cavity warms and filters air
• b. Trachea leads to the lungs. Held open with
  rings of cartilage. Also called windpipe
• c. Bronchus splits from trachea to each lung
• d. Lungs filled with alveoli
• Expands and contracts with help of diaphragm
• d. alveoli tiny air sacs surrounded by
  capillaries
• Oxygen diffuses into the capillaries to be taken
  to the cells throughout the body. Blood inflates
  alveoli with CO2 to be exhaled

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The Nervous System

• controls and coordinates functions throughout the
  body and responds to external and internal
  stimuli

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The Nervous System

• 1. Central Nervous System
• a. Brain Receives processes and sends
  information to different parts of the body.
• b. Spinal chord communications link between the
  brain and the rest of the body. Processes
  reflexes.

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The Nervous System

• 2. Peripheral Spinal Chord transmits impulses
  from the sense organs to the central nervous
  system

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The Endocrine System

• System of glands that deliver messages throughout
  the body by means of hormones
• Hormones work in antogonistic pairs

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The Endocrine System

• a. Pituitary glands master gland that
  secretes 9 different hormones and controls
  several other hormones
• b. Hypothalamus controls pituitary gland. Link
  between the nervous and endocrine systems
• c. Thyroid controls metabolism
• d. Adrenal glands fight or flight hormone
• e. Islets of Langerhans found in pancreas,
  secretes insulin and glucagons to control sugar
  levels.
• . Reproductive glands
• Ovaries estrogen
• Testes - testosterone