Animal Form and Function Flashcards
What is Anatomy and What is Physiology, and how are they connected
- Anatomy is the biological form of an organism
- Physiology is the study of biological functions an organism performs
- The comparative study of animals reveals form and function are inextricably linked
Form and function are intertwined, understanding both is required to understand the organism. Observation and Imagination link anatomy and physiology.
What affects the size and shape of an animal
- Size and shape affect the way an animal interacts with its environment
- Physical and chemical laws set the limits
- Gravity: As animals increase in size, skeletons must be proportionately larger to support their mass
- Also need strength for movement
- Diffusion of nutrients and heat exchange
- The body plan of an animal is programmed by the genome, itself the product of billions of years of evolution
How do the properties of water cause convergent evolution in aquatic animals
- Properties of water limit the possible shapes an animal can take that allow it to swim fast
- Evolutionary converge reflects how different species’ adapt to a similar environmental challenge in a similar way.
- Ex: How most fast swimmers have the same general shape. Dolphins, sharks, seals, penguins, fish.
How does size affect material exchange and usage by cells
- Materials such as nutrients, waste, products, and, heat and gases must be exchanges across the cell membranes of animal cells
- Rate of exchange is proportional to a cell’s surface area, whereas the amount of material needed to exchange is proportional to a cell’s volume (S/V ration is critical)
How do different types of organisms get their materials to their cells
- A single celled organism living in water has enough surface area to service the entire volume of its cytoplasm
- Multicellular organisms with a saclike body plan have body walls that are only two cells thick
- In flat animals like tapeworms, most cells are in direct contact with the environment
How have larger organisms adapted to get materials to all their cells
- Larger organisms have more complex internal organization
- Evolutionary adaptations such as specialized, extensively branched or folded structure, enable sufficient exchange with the environment
- In vertebrates, the space between cells is filled with interstitial fluid, which allows for the movement of material into and out of cells
how are animals organized
- most animals are composed of specialized cells organized into tissues that have different functions
- Tissues make up organs, which together make up organ systems
- Some organs, such as pancreas, belong to multiple organ systems
what are the four types of tissues
- Tissues are classified into four main categories:
- Epithelial
- Connective:
- Muscle:
- Nervous:
what are Epithelial cells
Closely joint cells that cover the outside of the body and lines organs and cavities within the body
what shapes can epithelial cells have
- the shape of epithelial cells:
- Cuboidal (like dice)
- Columnar (like bricks on end)
- Squamous (like floor tiles)
how can epithelial cells be arranged
- The arrangement of epithelial cells:
- Single cell layer (Simple)
- Stratified (multiple layers)
- Pseudostratified (single layer of cells of varying length)
what does polarization of tissues mean
Epithelial tissues are often polarized
One side can have different function and/or structure than the other side.
what are connective tissues
Scattered cells in a matrix (fibres + ground substance)
What can the scattered cells be in connective tissues
- Scattered cells: Fibroblasts, macrophages, mast cells, plasma cells, lymphocytes, leukocytes, adipose cells
what can the ground substance be in connective tissues
- ground substance holds everything together. Contains macromolecules, multi-adhesive glycoproteins (liquid, jellylike, or solid foundation)
what can the fibres be in connective tissues
- Fibres:
- Collagen fibres provide strength and flexibility
- Elastic fibres
- Reticular fibres join connective tissue to adjacent tissues
What are the six types of connective tissues in vertebrates
there are six types of connective tissue found in vertebrates:
- Loose connective tissue holds organs in place
- Fibrous connective tissue makes up tendons and ligaments
- bone is a mineralized connective tissue
- Adipose tissue makes up fat
- Blood, including blood cells and cell fragments in plasma
- Cartilage is a strong and flexible support material (avascular): Mainly chondrocytes
Connective tissues are all very vascular except for cartilage.
what are muscle tissues made form
Muscle cells: Actin and myosin together enable muscles to contract in response to nerve signals.
What are the three types of muscle tissue
There are three types of muscle tissue:
- Skeletal muscle or striated muscle is responsible for voluntary movement
- Smooth muscle is responsible for involuntary body activities.
- Cardiac muscle is responsible for contraction of the heart.
what are nervous tissues
Nervous tissue functions in the receipt, processing, and transmission of information
Nervous tissue contains
Neurons, which transmit nerve impulses (action potentials)
Glia, which help nourish, insulate, and regulate neuronal activity
How does the body communicate via the endocrine system
- The endocrine system transmits chemical signals called hormones to receptive cells throughout body via blood
- A hormone may affect one or more regions throughout the body
- Hormones are relatively slow acting, but can have long lasting affects
how does the body communicate via 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
- Nerve impulses can be received by neurons, muscle cells, endocrine cells, and exocrine cells
What is homeostasis
- Organisms use homeostasis to maintain a “steady state” or internal balance regardless of external environment
- In humans, body temperature, blood pH, and glucose concentration are each maintained at a constant level
- Mechanisms of homeostasis moderate changes in the internal environment
- For a give variable, fluctuations above or below a set point serve as a stimulus; these are detected by a sensor and trigger a response
- The response returns the variable to the set point
what is negative vs positive feedback
Negative Feedback:
The final product of an enzyme chain serves as an inhibitor preventing more of its production when enough is present.
Positive Feedback:
The final product of an enzyme chain speeds up the chain, increasing production of more of itself.
what type of feedback system does homeostasis rely on
- Homeostasis in animals relies largely on negative feedback, which returns a variable to a normal range
- Positive feedback amplified a stimulus and does not usually contribute to homeostasis in animals.
how does the body work to keep a system at homeostasis
The body usually have multiple systems that contribute to maintaining the homeostasis of a certain variable. Working together, they keep it stable. Often they work in opposition, (ex, one system heats, one cools body)
How does positive feedback help in labour
Estradiol from the ovaries activates oxytocin receptors on uterus
Oxytocin from the fetus and mother’s posterior pituitary gland stimulates uterus to contract, and stimulates placenta to make Prostaglandins which stimulate more contractions of uterus. Which produce more Oxytocin.
what are some ways homeostasis changes on a cyclic variation
- There are set points and normal ranges that can change with are or show cyclic variation
- In animals and plants a circadian rhythm governs physiological changes that occur roughly every 24 hours. (In humans body temp drops and melatonin concentration increases at night)
what is the difference between acclimation and acclimatization
- Animals are able to temporarily remodel their cells and tissues in response to changes in the external environment
- Adjust to a single environmental factor is called acclimation
- Adjustment to multiple factors is called acclimatization
What are endotherms
Endothermic organisms like mammals and birds generate heat internally to maintain body temperature
what are exotherms
Exothermic organisms like fish, reptiles and amphibians rely on external heat sources to regulate body temperature
what are thermoregulators
Thermoregulators like humans and basking reptiles actively maintain a stable body temperature
what are thermoconformers
Thermoconformers like many fish and invertebrates have body temperatures that match the external environment
what are homeotherms
Homeotherms like mammals and birds maintain a constant body temperature
what are Poikilotherms
Poikilotherms like reptiles and amphibians have body temperatures that fluctuate with the environment.
What other terms are often given to endotherms
Endothermic organisms are often homeotherms and thermoregulators (mammals and birds)
What other terms are often given to ectotherms
Ectothermic organisms are often poikilotherms and may be thermoconformers (e.g. reptiles and amphibians) though some ectotherms can thermoregulate behaviourally (e.g. basking in the sun, shivering; specialized circulation)
what are the four ways heat is exchanged
Organisms exchange heat by four physical processes:
- Radiation is emitted by all objects with a temperature above absolute zero
- evaporation: water has a high latent heat of vaporization
- Convection: fan effect
- Conduction: through direct contact with surfaces
what are the five adaptations to thermoregulation
Five adaptations help animals thermoregulate:
- Insulation
- Circulatory adaptations
- Cooling by evaporative heat loss
- Behavioural responses
- Adjusting metabolic heat production
How does insulation work
- Insulation is a major thermoregulator adaptation in mammals and birds
- skin, feathers, fur, and blubber reduce heat flow between animals and its environment
- insulation is especially important in marine mammals such as whales and walruses. They can maintain ~37ºC when ocean is near 0ºC without eating too much more
what are some circulator adaptations to thermoregulation
- Regulation of blood flow near the body surface significantly affects thermoregulation
- Many endotherms and ectotherms can alter amount of blood flowing between the body core and skin
- In vasodilation, blood flow in the skin increases, facilitating heat loss
- In vasoconstriction, blood flow in the skin decreases, lowering heat loss
describe Countercurrent heat exchangers, Rete Mirabile (wonderful nets)
The arrangements of blood vessels in many marine mammals and birds allows for countercurrent exchange
Countercurrent heat exchanges transfer heat between fluids flowing in opposite directions and thereby reduce heat loss
Some bony fishes and sharks also use countercurrent heat exchanges
Many endothermic insects have countercurrent heat exchangers that help maintain a high temperature in the thorax
how can animals cool by evaporative heat loss
- Many types of animals lose heat through evaporation of water from their skin
- Sweating or bathing moistens the skin, helping to cool and animals down
- Panting increases airflow over the tounge and therefore the cooling effect of evaporation. Seen in birds and many mammals (dogs, and even cats)
what are some behavioural responses to thermoregulation
- Both endotherms and ectotherms use behavioural responses to control body temperature
- Some terrestrial invertebrates have postures that minimize or maximize absorption of solar heat
- Honeybees huddle together during cold weather to retain heat
what is NST
Nonshivering thermogenesis (NST): primarily occurs in brown adipose tissue (BAT) a specialized type of fat that is rich in mitochondria and blood vessels
Cold triggers hormone release (Epienephrine) which acts on brown adipose tissue (BAT), stimulating the break down of fat via a PKA → lipase pathway = Fatty acids (FAs)
FA activate the uncoupling protein 1 (UCP1)/Thermogenisis; uncoupling oxidative phosphorylation from ATP production; producing heat instead of energy
In humans produce BAT is retained into adulthood, though it declines with age
what besides NST increases thermogenesis
Thermogenesis is increased by muscle activity such as moving or shivering
Some ectotherms can also shiver to increase body temperature
Moths will warm up before flying
How can animals adapt to seasonal temperature changes
Birds and mammals can vary their insulation to acclimatize to seasonal temperature changes
When temperature are subzero, some ectotherms produce “antifreeze” compounds to prevent ice formation in their cells.
