Zoology Unit 1 - Homeostasis & Physiology

what is homeostasis

Maintaining a stable environment inside an animal's body around a set point

what type of feedback is homeostasis

negative feedback

what systems control homeostasis

nervous and endocrine

positive feedback

pushes the body further out of homeostasis

(further from the set point) by maintaining the stimulation that deviated

from the set point

• If a level is too high, this feedback causes it to continue to increase the level

example of positive feedback

childbirth and blood clotting

negative feedbacl

returns the body to homeostasis (returns to

set point) by changing the direction of the stimulation that deviated from

the set point

• If a level is too high, this feedback brings the level down

• If a level is too low, this feedback brings the level back up

example of negative feedback

blood glucose, temperature, homeostasis

endothermic

animals use metabolism to maintain their body temperature

ectothermic

animals do not use metabolism to maintain their body temperature

• They bask in the sun or seek shade to change body temperature

examples of endothermic animals

mammals, birds

examples of ectothermic animals

fish, amphibians, reptiles

who needs more calories, ectotherms or endotherms

endothermic animals

Poikilothermic

animals allow their body temperature to fluctuate depending on

the environment

- usually ectotherms, but not always

homeothermic

animals, whether endotherms or ectotherms, maintain a constant

body temperature

what controls thermoregulation

nervous system, specifically hypothalamus

thermoregulation

To maintain homeostatic thermoregulation animals must be able to conserve heat

when it is cold outside and dissipate heat when it is hot outside

when its cold outside

• Thick fur/feathers

• Fat layer helps to maintain body temp

• Vasorestriction forces blood to the core of the body so heat is not lost through the skin

• Shivering is a last resort

• Ectotherms seek warmer areas

when its hot outside

• Panting or sweating

• Vasodilation brings blood (and heat) to skin, heat dissipates

• More surface area = more heat dissipation

• Ectotherms seek cooler areas

what is physiology

How form and function sustain life and shape responses to environmental

conditions

true or false: all animals have tissues, organs, and organ systems

false; some simple animals do not

even have tissues, much less organs and organ systems

musculoskeletal system

Provides support for the animal's body, internal organs, and the ability to

move

invertebrates musculoskeletal system

have exoskeleton

hard chitin or calcium exoskeleton have muscles that attach to

points inside the exoskeleton. Contraction creates movemen

Echnioderms

invertebrate that have a hydrostatic system that uses water pressure for movement

vertebrate musculoskeletal system

have an endoskeleton

bones, ligaments, tendons, catilage, and muscle

tendons join

muscle to bone

ligaments join

bone to bone

what is hydrolyzed in the digestive system

large macromolecules (protein, carbs, fat) into their smaller components (amino acids, glucose, fatty acids, etc.)

what system does the digestive work closely with

circulatory system

circulatory system

• Transports nutrients and gases throughout the body

• The heart is the "motor" of the circulatory system, creating the circulation

of blood through blood vessels

arteries carry

oxygenated blood away from the heart to the body

veins carry

deoxygenated blood from the body to the heart

capillaries connect

arteries to veins

• They have thin walls that allow diffusion of gases, nutrients, water, etc.

what system does the circulatory system work with

respiratory system, the digestive

system, and the urinary system

respiratory system

• This system absorbs oxygen and remove carbon dioxide

• Oxygen is absorbed and transported to cells throughout the body

• Carbon dioxide, a waste product, is transported from cells, and released

out of the body

the complexity of the respiratory system is directly related

the size of the animal

excretory system

• Eliminates nitrogenous waste from the body, regulates blood volume and

blood pressure, control levels of electrolytes and metabolic waste, and

regulates blood pH

parts of the excretory system

kidneys, bladder, urethra

nervous sytem

• Coordinates its actions and sensory information by transmitting signals to

and from different parts of its body

• Processes sensory information from both outside and inside the body

parts of the nervous system

brain, nerves

sensory system

considered part of the nervous system responsible for processing

sensory information; consists of sensory neurons, neural pathways, and parts of the brain involved in sensory perception and interoception

- sight, sound, smell, taste, touch

reproductive system

Anatomical organs involved in sexual reproduction. Many non-living

substances such as fluids, hormones, and pheromones are also important

accessories to the reproductive system

gonads produce

eggs and sperm