BIO 121 EXAM 2 STUDY GUIDE | 2026 ACTUAL
STUDY | VERIFIED STUDY | GUARANTEED
PASS
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Biology Exam 2
Structure and function are closely linked at every level of organization o The
function is possible because the structure is there (not visa versa)
4 Main Animal Tissue
1. Muscular- provide contractile force
2. Connective- elasticity, structure support, connects things
3. Nervous- signals over distances with electrical impulses (short distances-
neurotransmitter chemicals)
4. Epithelial- lines insides
• Animals do not have vascular tissue
• Main type of tissue in plants (xylem and phloem) is vascular
Epithelial Tissue (Epithelium)
• Continuous layer (sheet) of cells o Covering a body surface o Lining a body cavity
• Functions in protection, absorption, secretion, and sensation
Connective Tissue 1
• Few cells separated by intercellular substance (Cells they do not perform the basic
functions) functions of cells are dependent on what’s around the cells o Fibers
scattered through a matrix
• Intercellular substance fibers (usually protein fibers) lots of materials that are
produced by the cells but done by the matrix o Collagen fibers o Elastic fibers o
Reticular fibers
• Fibers can be in liquid matrix, mineralized calcium matrix
Connective Tissue 2
Contains specialized cells o Fibroblasts (osteocytes mineralized matrix and forms bone)
and macrophages break down and release the blood back to the body from the
calcium stolen from bones
o Bones are made from calcium if blood levels of calcium go down in your body the
body will take calcium from the bones to maintain homeostasis
Functions
o Joins other body tissues o
Supports body and organs o
Protects underlying organs``
Adipose tissue
Muscle Tissue
• Consists of cells specialized to contract
• Each cell is elongated muscle fiber o Many contractile units called myofibrils Nervous
Tissue
Neurons
• Elongated cells
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• Specialized for transmitting impulses
• Glial cells they do not send messages
• Support and nourish neurons
The Basic Tissue Types
1. Epithelial, muscle, connective, nervous
2. Work together in the structure and function of organs
Organ Systems
1. Integumentary
2. Skeletal
3. Muscular
4. Digestive
5. Cardiovascular
6. Immune (lymphatic)
7. Respiratory
8. Urinary
9. Nervous
10. Endocrine
11. Reproductive
Homeostasis
• Balanced internal environment (steady state)
• Homeostatic mechanisms o Control processes that maintain
conditions o Release feedback
Microphone feedback is positive
Negative feedback
Stressor
1. Causes deviation from set point
2. Sensor detects change from set point
3. Sensor signals integrator (control center)
4. Integrator activates effectors (homeostatic mechanisms)
5. Normal condition (set point) restored
6. Homeostasis
Positive Feedback- signal and the loop of feedback leads to stronger more of the same,
amplifies
- Contractions of childbirth (contractions are closer together then the baby is coming v soon)
Stressor: hemorrhage
1. Loss of blood causes blood pressure to decrease
2. Less blood circulates to heart
3. Heart function declines
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4. Cardiac output decreases (heart pump less blood)
Deviation from steady state causes that intensify (rather than reverse) the changes
Negative Feedback
Stressor deviation from set point sensor detects change from set point sensor signals
integrator (brain) integrator activates effectors (homeostatic mechanisms) normal condition
(set point) restored homeostasis
Positive Feedback
Stressor: hemorrhage
1. Loss of blood causes blood pressure to decrease
2. Less blood circulates to heart
3. Heart function declines
4. Cardiac output decreases (heart pump less blood)
Deviation from steady state causes that intensify (rather than reverse) the changes
Thermoregulation
• Process of maintaining body temperature within certain limits o
Despite changes in surrounding temperature o Cold outside try to
maintain body temperature (98 F)
• Animals have different structural, behavioral, and physiological
strategies
Ectotherms o Body temp depends on temp of
environment
Stay at the bottom of the ocean
Lizard in the hot, body temp will rise o Use
behavioral strategies to adjust to body temperatures
o Have homeostatic mechanisms regulate body temp within a narrow range
Endotherms- mammals can keep their body temperature regulated despite the environment
they are living in
• Costs and Benefits o Ectothermy- little energy used to maintain the
metabolic rate o Ectotherms can survive on less food
• Disadvantage of ectothermy o Activity limited by daily and seasonal
temperature conditions o When the sun is up their body
temperature is warmed
Endotherms
- Homeostatic mechanisms o Regulate body temp within a narrow range
- Birds feathers keep them warm but they need more food
- Benefits of endothermy o High metabolic rate
o Constant body temp allows higher rate of enzyme activity
STUDY | VERIFIED STUDY | GUARANTEED
PASS
, lOMoAR cPSD| 61371432
Biology Exam 2
Structure and function are closely linked at every level of organization o The
function is possible because the structure is there (not visa versa)
4 Main Animal Tissue
1. Muscular- provide contractile force
2. Connective- elasticity, structure support, connects things
3. Nervous- signals over distances with electrical impulses (short distances-
neurotransmitter chemicals)
4. Epithelial- lines insides
• Animals do not have vascular tissue
• Main type of tissue in plants (xylem and phloem) is vascular
Epithelial Tissue (Epithelium)
• Continuous layer (sheet) of cells o Covering a body surface o Lining a body cavity
• Functions in protection, absorption, secretion, and sensation
Connective Tissue 1
• Few cells separated by intercellular substance (Cells they do not perform the basic
functions) functions of cells are dependent on what’s around the cells o Fibers
scattered through a matrix
• Intercellular substance fibers (usually protein fibers) lots of materials that are
produced by the cells but done by the matrix o Collagen fibers o Elastic fibers o
Reticular fibers
• Fibers can be in liquid matrix, mineralized calcium matrix
Connective Tissue 2
Contains specialized cells o Fibroblasts (osteocytes mineralized matrix and forms bone)
and macrophages break down and release the blood back to the body from the
calcium stolen from bones
o Bones are made from calcium if blood levels of calcium go down in your body the
body will take calcium from the bones to maintain homeostasis
Functions
o Joins other body tissues o
Supports body and organs o
Protects underlying organs``
Adipose tissue
Muscle Tissue
• Consists of cells specialized to contract
• Each cell is elongated muscle fiber o Many contractile units called myofibrils Nervous
Tissue
Neurons
• Elongated cells
, lOMoAR cPSD| 61371432
• Specialized for transmitting impulses
• Glial cells they do not send messages
• Support and nourish neurons
The Basic Tissue Types
1. Epithelial, muscle, connective, nervous
2. Work together in the structure and function of organs
Organ Systems
1. Integumentary
2. Skeletal
3. Muscular
4. Digestive
5. Cardiovascular
6. Immune (lymphatic)
7. Respiratory
8. Urinary
9. Nervous
10. Endocrine
11. Reproductive
Homeostasis
• Balanced internal environment (steady state)
• Homeostatic mechanisms o Control processes that maintain
conditions o Release feedback
Microphone feedback is positive
Negative feedback
Stressor
1. Causes deviation from set point
2. Sensor detects change from set point
3. Sensor signals integrator (control center)
4. Integrator activates effectors (homeostatic mechanisms)
5. Normal condition (set point) restored
6. Homeostasis
Positive Feedback- signal and the loop of feedback leads to stronger more of the same,
amplifies
- Contractions of childbirth (contractions are closer together then the baby is coming v soon)
Stressor: hemorrhage
1. Loss of blood causes blood pressure to decrease
2. Less blood circulates to heart
3. Heart function declines
, lOMoAR cPSD| 61371432
4. Cardiac output decreases (heart pump less blood)
Deviation from steady state causes that intensify (rather than reverse) the changes
Negative Feedback
Stressor deviation from set point sensor detects change from set point sensor signals
integrator (brain) integrator activates effectors (homeostatic mechanisms) normal condition
(set point) restored homeostasis
Positive Feedback
Stressor: hemorrhage
1. Loss of blood causes blood pressure to decrease
2. Less blood circulates to heart
3. Heart function declines
4. Cardiac output decreases (heart pump less blood)
Deviation from steady state causes that intensify (rather than reverse) the changes
Thermoregulation
• Process of maintaining body temperature within certain limits o
Despite changes in surrounding temperature o Cold outside try to
maintain body temperature (98 F)
• Animals have different structural, behavioral, and physiological
strategies
Ectotherms o Body temp depends on temp of
environment
Stay at the bottom of the ocean
Lizard in the hot, body temp will rise o Use
behavioral strategies to adjust to body temperatures
o Have homeostatic mechanisms regulate body temp within a narrow range
Endotherms- mammals can keep their body temperature regulated despite the environment
they are living in
• Costs and Benefits o Ectothermy- little energy used to maintain the
metabolic rate o Ectotherms can survive on less food
• Disadvantage of ectothermy o Activity limited by daily and seasonal
temperature conditions o When the sun is up their body
temperature is warmed
Endotherms
- Homeostatic mechanisms o Regulate body temp within a narrow range
- Birds feathers keep them warm but they need more food
- Benefits of endothermy o High metabolic rate
o Constant body temp allows higher rate of enzyme activity
