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Questions and Answers
What is the smallest functional unit of life?
What is the smallest functional unit of life?
Negative feedback mechanisms enhance the changes in the body's conditions.
Negative feedback mechanisms enhance the changes in the body's conditions.
False
Name the four main types of tissues in the body.
Name the four main types of tissues in the body.
Epithelial, connective, muscle, nervous
The __________ is made up of different tissue types working together to perform a specific function.
The __________ is made up of different tissue types working together to perform a specific function.
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Match the level of organization with its description:
Match the level of organization with its description:
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Which tissue type is responsible for transmitting electrical signals in the body?
Which tissue type is responsible for transmitting electrical signals in the body?
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Homeostasis refers to the body's ability to maintain a stable internal environment.
Homeostasis refers to the body's ability to maintain a stable internal environment.
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What happens to the body during thermoregulation when it gets too hot?
What happens to the body during thermoregulation when it gets too hot?
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The __________ is formed by a phospholipid bilayer that regulates what enters and leaves a cell.
The __________ is formed by a phospholipid bilayer that regulates what enters and leaves a cell.
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Which of the following is an example of positive feedback?
Which of the following is an example of positive feedback?
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Which of the following transport mechanisms requires energy (ATP)?
Which of the following transport mechanisms requires energy (ATP)?
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Osmosis involves the movement of solutes across a semipermeable membrane.
Osmosis involves the movement of solutes across a semipermeable membrane.
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What is the primary function of exocrine glands?
What is the primary function of exocrine glands?
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The type of muscle tissue responsible for involuntary control and found in the heart is called _____ muscle.
The type of muscle tissue responsible for involuntary control and found in the heart is called _____ muscle.
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Match the following terms with their definitions:
Match the following terms with their definitions:
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Which of the following structures is part of the axial skeleton?
Which of the following structures is part of the axial skeleton?
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Stratified squamous epithelium is found in the intestines.
Stratified squamous epithelium is found in the intestines.
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What is the function of parathyroid hormone (PTH)?
What is the function of parathyroid hormone (PTH)?
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The _____ tissue type is primarily responsible for covering and lining surfaces in the body.
The _____ tissue type is primarily responsible for covering and lining surfaces in the body.
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Which of the following correctly describes isotonic solutions?
Which of the following correctly describes isotonic solutions?
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Study Notes
Levels of Organization
- Chemical Level: Atoms (basic building blocks like hydrogen, oxygen, carbon) combine to form molecules (e.g., water, proteins, DNA). Essential for all biological structures and functions.
- Cellular Level: Cells are the smallest functional units of life. Cells contain organelles (e.g., mitochondria, nucleus) working together to maintain life. A muscle cell's contraction, for example, produces movement.
- Tissue Level: Tissues are groups of similar cells with a common function. Four main types: epithelial (cover body surfaces, e.g., skin), connective (support and bind, e.g., bone, blood), muscle (facilitate movement, e.g., skeletal, cardiac, smooth), and nervous (transmit electrical signals, e.g., neurons).
- Organ Level: Organs are composed of different tissue types working together for a specific function. The heart, for example, includes muscle, connective, and nervous tissues.
- Organ System Level: Organ systems are groups of organs working together to perform complex functions. The digestive system includes the stomach, intestines, and liver.
- Organismal Level: The complete human body with organ systems functioning together.
Homeostasis
- Homeostasis: Maintaining a stable internal environment despite external fluctuations.
- Negative Feedback Mechanisms: The body counters changes to return to homeostasis. Example: Thermoregulation. If too hot, sweating and vasodilation occur; if too cold, shivering and vasoconstriction occur.
- Positive Feedback Mechanisms: Intensify a change rather than counteracting it. Example: Childbirth. Oxytocin release intensifies contractions, which further releases oxytocin, continuing the process until delivery.
Membranes and Transport Mechanisms
- Plasma Membrane: Phospholipid bilayer regulating what enters and leaves the cell.
- Selective Permeability: Some substances pass freely (oxygen, carbon dioxide), others are restricted (large molecules, ions).
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Passive Transport: No energy (ATP) required.
- Diffusion: Movement from high to low concentration (e.g., oxygen entering bloodstream).
- Osmosis: Water movement across a semipermeable membrane.
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Active Transport: Requires energy (ATP) to move molecules against their concentration gradient.
- Na+/K+ Pump: Actively transports sodium ions out and potassium ions in, maintaining resting membrane potential.
Protein Synthesis
- Transcription: Copying a gene's DNA sequence into mRNA in the nucleus.
- Translation: mRNA is translated into an amino acid sequence at a ribosome in the cytoplasm. tRNA brings amino acids, and the ribosome builds the protein.
Tonicity
- Hypertonic: Higher solute concentration outside the cell. Water moves out, cell shrinks.
- Hypotonic: Lower solute concentration outside the cell. Water moves in, cell swells.
- Isotonic: Equal solute concentrations inside and outside the cell. No net water movement.
Endocrine vs. Exocrine Glands
- Endocrine Glands: Secrete hormones directly into the bloodstream (e.g., thyroid, pancreas).
- Exocrine Glands: Secrete substances through ducts to an external or internal surface (e.g., sweat glands, salivary glands).
Four Main Tissue Types
- Epithelial Tissue: Functions in protection, secretion, absorption, filtration. Example: stratified squamous epithelium protects the skin. Simple columnar epithelium in intestines aids in absorption.
- Connective Tissue: Functions in support, protection, storage, transportation. Types: Bone, blood, adipose tissue, cartilage. Bone supports, blood transports nutrients & waste, adipose stores energy, and cushions.
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Muscle Tissue:
- Skeletal: Voluntary, striated, for movement.
- Cardiac: Involuntary, striated, in the heart.
- Smooth: Involuntary, non-striated, in internal organs.
- Nervous Tissue: Transmits electrical signals. Composed of neurons (transmit messages) and neuroglia (supporting).
Integumentary System (Skin)
- Skin: Largest organ, composed of epidermis (outer, keratinocytes), dermis (blood vessels, nerves), and hypodermis (fat, insulation).
- Functions: Protection (UV light, pathogens), temperature regulation (sweating), sensation (pain, pressure, temperature), vitamin D synthesis (UV exposure).
Skeletal System
- Axial Skeleton: Skull, vertebral column, rib cage. Supports and protects.
- Appendicular Skeleton: Limbs and girdles (shoulder, pelvic). Attaches limbs.
- Bone Classifications: Based on shape: long (levers, femur), short (stability, carpals), flat (protection, skull), irregular (complex, vertebrae).
- Bone Cells: Osteoblasts build bone, osteoclasts break it down, osteocytes maintain.
- Bone Structure: Compact bone (outer layer, dense), spongy bone (inner layer, lighter, support).
- Bone Homeostasis: PTH (parathyroid hormone) increases blood calcium by stimulating osteoclasts, calcitonin decreases blood calcium by inhibiting osteoclasts.
Muscular System
- Muscle Tissue Types: Skeletal (voluntary, striated), cardiac (involuntary, striated), smooth (involuntary, non-striated).
- Muscle Contraction: Sliding filament theory (actin slides over myosin). ATP required.
- Metabolism: Anaerobic (without oxygen, less ATP, lactic acid), aerobic (with oxygen, more ATP).
Nervous System
- Central Nervous System (CNS): Brain and spinal cord; processes information and sends commands.
- Peripheral Nervous System (PNS): All nerves outside the CNS; carries sensory and motor information.
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Neurons:
- Structure: Dendrites receive signals, axon transmits to axon terminals (release neurotransmitters).
- Action Potential: Rapid change in neuronal membrane charge.
- Resting Potential: Negative inside the neuron.
- Depolarization: Inside becomes more positive.
- Repolarization: Returns to resting potential.
- Neurotransmitters: Acetylcholine (muscle contraction), norepinephrine (fight-or-flight).
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Description
Explore the various levels of biological organization, from the chemical level to the organ system level. This quiz covers the fundamentals of how atoms, cells, tissues, organs, and organ systems work together to sustain life. Test your knowledge on these essential concepts of biology.
