Lecture 18 coordination, communication and homeostasis Flashcards
What makes up organs
Tissues (specialized cells organized into tissues)
4 main categories of animal tissues
- Epithelial tissues
- Connective tissues
- Nervous tissues
- Muscular tissues
Epithelial tissue
Covers the outside of the body and lines the organs and cavities w/in the body.
The cells are closely joined together
The shape of the cells can be cuboidal (like dice), columnar (like bricks on end),
or squamous (like floor tiles)
What does Connective tissue do
Hold organs and tissue together
What causes muscle tissue to have contractions
Myosin protein - muscle contraction
Skeletal muscle
-attatched to bones by tendons
-is responsible for voluntary movement
-consist of bundles of large cells called muscle fibers
-building muscle increases size but not amount of muscle fibers
Smooth muscle
-lacks striations
-found in the walls of the digestive tract, urinary bladder, arteries, etc
-cells are spindled shaped
-responsible for involuntary body activities (churning of the stomach and constrictions of arteries)
Cardiac muscle
-forms the contractile wall of the hearts
-striated like skeletal muscle and has similar contractile properties
-has branched fibers that interconnect via intercalated disks; they relay signals from cell to cell and help synchronize heart contraction
Nervous tissue
● Receive, process and transmit information
● Neurons and glial cells
Nervous tissue (brain and spinal cord)
Central Nervous System (CNS)
Nervous tissue (nerves)
Peripheral Nervous System (PNS)
Examples of how the body exchanges with the environment
Exchange with the environment
(ex. respiratory system, excretory system, digestive system)
In order to maintain homeostasis what does it require?
energy/atp
Bioenergetics
-overall low and transformation of energy in animals
-determines animals overall nutrition need, and it relates to an animals size, activity, and environment
Metabolic rate
the sum of all the energy an animal uses in a unit of time
Metabolic rate can be determined by…
● An animal’s heat loss
● The amount of oxygen consumed or carbon dioxide
produced
● Measuring energy content of food consumed and energy
lost in waste products
Size and metabolic Rate (BMR)
Same species: Metabolic rate is proportional to body
mass to the power of three-quarters (m3/4).
Different species
Smaller animals have
higher metabolic rates
per kilogram than larger
animals.
Miscommunication within body
Diabetes Mellitus
Miscommunication between pancreas and glucose storage tissues (Liver and muscles).
Lou Gehrig’s disease (ALS)
No communication between the brain and muscles
Venoms
King Cobra venom blocks communication to muscles
endocrine system (coordination and control)
● The endocrine system releases
signaling molecules called hormones
into the bloodstream
● A hormone may affect one or more
regions throughout the body
● Hormones are relatively slow acting,
but can have long-lasting effects
The nervous system
● The nervous system transmits
information between specific locations
● The information conveyed depends on a
signal’s pathway, not the type of signal
● Nerve signal transmission is very fast
Mechanisms of homeostasis
Mechanisms of homeostasis moderate changes in the international environment
For a given variable, fluctuations above or below a set point serve as a stimulus; these are detected by a sensor.
A control center then generates output that triggers a response.
The response returns the variable to the set point.
Positive feedback
amplifies a stimulus and does not
usually contribute to homeostasis in animals.
Negative feedback
helps to return a variable to a
normal range. (animals relies largely on this)
Negative feedback loops in Homeostasis
The dynamic equilibrium of homeostasis is maintained by negative feedback, which helps to return a variable to a normal range. (think of shivering and sweating example)
Thermoregulation
is the process by which animals maintain an internal temperature within a normal range.
(shivering and sweating)
Homeostasis
used to maintain a “steady state” or internal balance regardless of external environment
body temp, blood pH and glucose conc are each maintained at a constant level
Endothermic (Endothermy)
animals generate heat by metabolism; birds and mammals are endotherms
Ectothermic (Ectothermy)
animals gain heat from external sources; ectotherms include most invertebrates, fishes,
amphibians, and nonavian reptiles
Endothermy vs Ectothermy
● Endotherms can maintain a stable body temperature even in the face of large fluctuations in environmental temperature.
● Endothermy is more energetically expensive than ectothermy.
● In general, ectotherms tolerate greater variation in internal temperature.
Alternations in Homeostasis
Set points and normal ranges can change with age or show cyclic variation.
In animals and plants, a circadian rhythm governs physiological changes that occur roughly every 24 hours.
Acclimatization
Homeostasis can adjust to changes in external environment with this process
Acclimatization is a temporary change during
an animal’s lifetime.
Adaptation
when some heritable traits aid in survival, individuals with this trait will produce more offsprings that survive as well and will pass on this trait, increasing the frequency of these traits in the next generation
