Unit 4: Animals Flashcards
Definition: Diffusion
Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration.
Definition: Single-Celled Organisms
In single-celled organisms, diffusion allows direct exchange with the environment, facilitating nutrient uptake and waste removal.
Definition: Cell Membrane
All substances must pass through the cell membrane to enter or exit the cell, maintaining a controlled internal environment.
Definition: Interstitial Fluid
This fluid surrounds all cells, facilitating the exchange of nutrients and wastes.
Why is diffusion inadequate for transporting chemicals through thick bodies like humans?
The time it takes for diffusion increases exponentially with distance.
Which organs are primarily involved in the diffusion of gases, nutrients, and wastes in multicellular organisms?
Lungs, intestines, kidneys
Nutrient and Waste Exchange: Definition: Capillary Transport
Oxygen-rich blood is transported to body tissues via small capillaries.
Nutrient and Waste Exchange: Definition: Exchange Process
Oxygen diffuses from blood to interstitial fluid, while waste products and carbon dioxide move from interstitial fluid to blood.
Nutrient and Waste Exchange: Definition: Efficient Exchange
By ensuring short diffusion distances, the body maintains efficient nutrient delivery and waste removal.
Nutrient and Waste Exchange: Definition: Circulatory Function
Frequent circulation of blood through exchange organs helps maintain homeostasis.
What must surround every living cell to allow substances to permeate the membrane?
Water
In the context of diffusion, what is meant by the term “internal pond”?
The water that surrounds the external environment of the cell.
Definition: The Circulatory System
System that transports nutrients, blood, and waste around the body.
Definition: Plasma
The liquid part of the blood, making up about 55% of its volume. It contains water, proteins, glucose, hormones, and waste products.
Definition: Red Blood Cells (RBCs)
Cells that carry oxygen from the lungs to the body and bring carbon dioxide back to the lungs to be expelled.
Definition: White Blood Cells (WBCs)
Cells involved in immune response, defending the body against infection and disease.
Definition: Platelets
Small cell fragments that play a key role in blood clotting and wound healing.
Functions of Blood: Transportation
Carries oxygen, nutrients, hormones, and waste products to and from cells.
Functions of Blood: Regulation
Helps regulate body temperature, pH levels, and fluid balance.
Functions of Blood: Protection
Contains immune cells that protect against pathogens and has clotting factors to prevent excessive bleeding.
Definition: Arteries
Thick-walled vessels that carry blood away from the heart under high pressure. They branch into smaller arterioles and eventually capillaries.
Definition: Veins
Thinner-walled vessels that carry blood toward the heart under lower pressure. They have valves to prevent backflow.
Definition: Capillaries
The smallest blood vessels where the exchange of gases, nutrients, and waste occurs between blood and tissues.
Which vessels carry blood away from the heart?
Arteries
What prevents blood from slipping backward on the compression stroke of the heart?
Valves
Heart: Definition
The human heart is a cone-shaped organ, roughly the size of a fist.
Heart: Location
Positioned beneath the sternum, slightly to the left.
Heart: Pericardium
Double-layered sac enclosing the heart, with fluid between layers, allowing smooth movement during heartbeats.
What is the primary function of the pericardium sac surrounding the heart?
To enable the layers to slide over each other during heartbeats.
Anatomy of the Heart: Structure
The heart is a muscular organ divided into four chambers: two atria and two ventricles.
Anatomy of the Heart: Right Atrium and Ventricle
Receive deoxygenated blood and pump it to the lungs.
Anatomy of the Heart: Left Atrium and Ventricle
Receive oxygenated blood from the lungs and pump it to the body.
Anatomy of the Heart: Valves
Ensure one-way blood flow through the heart, preventing backflow.
Blood Flow Through the Heart: Right Side
Blood enters the right atrium via the superior and inferior vena cava.
Blood Flow Through the Heart: Left Side
Returns from the lungs via the pulmonary veins to the left atrium.
What is the main function of the atria in the heart?
Receive blood returning to the heart.
Definition:Pulmonary Arteries
Carry deoxygenated blood to the lungs.
Definition: Pulmonary Veins
Return oxygenated blood from the lungs.
Definition: Aorta
Distributes oxygenated blood to the body.
Definition: Tricuspid Valve
Between right atrium and right ventricle.
Definition: Pulmonary Valve
Between right ventricle and pulmonary artery.
Definition: Mitral Valve
Between left atrium and left ventricle.
Definition: Aortic Valve
Between left ventricle and aorta.
Definition: Systemic Circulation
Blood flow from the heart to the body and back.
Definition: Pulmonary Circulation
Blood flow from the heart to the lungs and back.
Definition: Cycle
Describes how blood is oxygenated in the lungs and distributed to the body.
Definition: Oxygenation
Blood picks up oxygen and releases carbon dioxide in the lungs.
Definition: Distribution
Oxygenated blood is sent throughout the body to deliver oxygen to tissues.
What is the primary function of the SA node in the heart?
To regulate the heart rate.
Which blood vessels bring blood to the heart from the general body circulation?
Superior and inferior vena cavas.
Definition: Heart Cycle
The heart cycle consists of systole (contraction) and diastole (relaxation).
Definition: Systole
Contraction phase