Digestive System Review

What are the main functions of the digestive system?

What are the main functions of the digestive system?Digesting FoodAbsorbing NutrientsEliminating Waste

Why is the pancreas important for digestion?

Why is the liver important for digestion?

Why is the gall bladder important for digestion?

Why is the pancreas important for digestion?

• Releases enzymes that digest starch, proteins, and fats.

Why is the liver important for digestion?Produces Bile- helps breakdown fats

Why is the gall bladder important for digestion?

Stores Bile

What important hormones are released by the Pancreas?

What important hormones are released by the Pancreas?

Glucagon & Insulin

Relate negative feedback systems to the maintenance of homeostasis.

Relate negative feedback systems to the maintenance of homeostasis.

Feedback systems • monitor certain factors (such as hormone level

in the blood) • relay information back to the source (such as

the gland that produces the hormone)• system adjusts accordingly

Feedback systems constantly monitor and adjust in the body in order to maintain

homeostasis.

In order for the body to maintain homeostasis, the chemical decomposition of food to produce energy must be followed by

A) water intake.B) muscle contractions.C) waste removal.D) nervous impulses.

What to Study

• The main Organs and their Functions in the Digestive system.

• The main Endocrine System structures– Hypothalamus– Pituitary gland– Thyroid Gland– Parathyroid Gland

• What is a target cell and receptor?• What is a negative Feedback Loop?

The Nervous System

Nervous System• The basic unit of

structure and function is the neuron, or nerve cell.

• Neurons- conduct impulses “messages” through out the nervous system

1. Dendrites receive the message, and process it.

2. Message is sent down the axon

1. Dendrites receive the message, and process it.

2. Message is sent down the axon

3. Axon terminals release neurotransmitters to the next cell.

How do Neurons work?• At Rest: More potassium ion inside the cell

and more sodium outside of the cell. (sodium potassium pump- pumps 3 sodiums out for every 2 potassiums that are pumped in)

• The cell is said to be “Polarized” + on the outside of the cell- on the inside

How do Neurons work?

• When a stimulus excites a neuron: gated sodium channels open up and sodium rushes into the cell. A wave of + charges moves down the cell. From Dendrites to Axons.

How do Neurons work?

• When a stimulus excites a neuron: gated sodium channels open up and sodium rushes into the cell. A wave of + charges moves down the cell. From Dendrites to Axons.

• Once the signal reaches the end of the axon,

neurotransmitters are released. These neurotransmitters travel across the synapse and reach the dendrites of the next neuron starting the process again.

3 Types of Neurons:

1. Sensory – send impulses from the body, “senses”, to the brain and spinal cord

2.Interneurons- Found in the brain and spinal cord. They are the decision makers or “thought”

3.Motor Neurons- carry the response from the brain or spinal cord back to a muscle or gland.

Reflex: An involuntary reaction in response to a stimulusReflex Arc: The path along which an impulse must travel to

bring about a reflex.

Divisions of the Nervous System

Central Nervous System• Brain and

Spinal Cord

Peripheral Nervous System• All of the nerves

2 Parts:i. Somaticii. Autonomic

The nervous system has two components:

Somatic Nervous system- sends information to and receives information from muscles and sensory organs. – plate is hot– bladder is full

Autonomic Nervous System- Controls internal organs** involuntary responses**

– controls muscles of the lungs– release of hormones, epinephrine – heart rate– Body Temperature– Digestion

Onto the Respiratory System

The Respiratory System

The Respiratory System

• Function: Exchange gasses– O2 (in)– CO2 (out)

The Pathway of Air

1) Trachea2) Bronchi3) Bronchioles4) Alveoli

Alveoli• The actual site of gas exchange• Gas exchange occurs through the process of

diffusion

The Circulatory System

Transports blood throughout the body

The Circulatory System

Transports blood throughout the body• Heart: muscle that pumps blood throughout

the body• Arteries: Take blood away from the heart to

the lungs and body• Veins: Return blood to the heart

Blood• Transports nutrients and gasses throughout

the body

Urinary System

Function: Filter blood to remove waste, maintaining homeostasis of bodily fluids• Kidneys• Ureters• Bladder

Kidney• Nephron: functional unit with in the kidney. – Where the filtration actually takes place.

The major waste product is nitrogen waste, from the breakdown of proteins. – ammonia and urea Form urine

Kidneys also….

• Control sodium levels in the blood• Regulate pH (acidity)

The End

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