EEMB 7 Exam 2 - Summer

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anatomy

biological forms

• structure

physiology

biological function

• form indicates function

hierarchy of complexity

cells —> tissues —> organs —> organ systems —> organism

muscle tissue

a specialized soft tissue made of cells that can shorten and contract

skeletal tissue

specialized connective tissues that for the structural framework of the body, support and protect organs, and enable movement

• ex: cartilage, ligaments, tendons, bone

connective tissue

a primary biological group of cells, fibers, and gel-like ground substance that supports, protects, binds, and gives structure to other tissues and organs in the body

two recurring themes in animal physiology

homeostasis and specificity

homeostasis

body’s effort to regulate and maintain internal physical conditions within narrow limits

specificity

chemical reactions will only result when certain participants are involved

Endocrine system and Nervous system similarites

coordination and control

• responses to stimuli

• both systems enable information flow among cells, tissues, and organs

• differences through signals are adapted for different functions

endocrine system

• slow and sustained signals

• can act on many cell types

• chemically based

• energetically different

nervous system

• fast and fleeting signals

• specific acts on one or few cells

• electrically based

• takes a lot of energy

humeral trigger

• endocrine system stimuli

substance too low —> stimulates to release more hormone

neuronal trigger

• endocrine system stimuli

neuron directly stimulates gland

hormonal trigger

• endocrine system stimuli

endocrine system releases hormone that stimulates another endocrine gland to release hormone

simple endocrine pathway

respond to internal or environemntal stimulus by secreting specific hormone

nerve impulses

entire system adapted for directing immediate and rapid response to environment

hormones

entire system adapted for coordinating gradual changes that effect entire body

hormone definition

1. secreted by endocrine gland

2. relatively small amount secreted

3. travels in bloodstream

hormone - major concept

lock and key mechanism

• hormones have specific 3D shape

• receptors must have specific negative 3D shape to hormone

three major categories of hormones

• amine - amino acid derivative

• peptide - < 100 amino acids

• steroids - lipid four-ringed structure (starts with cholesterol)

endocrine glands

produce hormones

• secrete hormones directly into surrounding fluids

two methods of regulation

negative and positive feedback loops

negative feedback loop

recognizes deviation from set point by sensors —> sends info to integrator —> responds through effector which has an opposite or diminishing effect on originating variable

• works in opposite direction

• ex: sweating when too hot and shivering when too cold

positive feedback loop

initiation event or stimulus causes change in variance

• receptors sense change in variable

• control center compares against reference value

• effectors make adjustments in same direction as initiation event, furthers output (loop)

ex: during childbirth, pressure on the cervix triggers oxytocin release, which causes stronger urine contractions, pushing the baby harder and creating more pressure until birth

pituitary gland main function

make and release vital hormones that control growth, metabolism, reproduction, and stress responses while directing other endocrine glands throughout your body to function properly

pituitary gland - anterior

regulated through vessels connected to hypothalamus

• often part of a very complex hormone cascade: one signals release, signals others too

• range in function from reproduction and growth to metabolism and stress response

pituitary gland - posterior

• regulated through nerves connected to hypothalamus

releases two vital hormones made by the hypothalamus

1. ADH: controls water balance and blood pressure - water gets reabsorbed, urine gets concentrated, and blood osmolarity returns to normal setting (homeostasis)

2. oxytocin - supports childbirth, breastfeeding, and social bonding

epinephrine

fight or flight: made by adrenal glands during stress, fear, or danger

• used to treat allergic reactions

• energy surge

• endocrine system

feedback control - regulator

internal mechanism controls internal change

feedback control - conformer

internal conditions change in response to external change

• i.e. response to cold water

thermoregulation - ectotherms

generate body heat metabolically but cannot maintain constant internal body temperature

• ex: reptiles, amphibians, fish, most invertebrates

thermoregulation - endothermic

generate body heat metabolically, body temp does not match environmental temp.

• ex: polar bears

countercurrent exchange

mechanism between two flowing bodies flowing in opposite directions to each other - keeps a concentration or temperature difference going the whole way through and allows body to move heat, oxygen, or salts very well

• trap heat in body —> reduces heat loss from extremities

• circulatory adaptation for thermoregulation

osmoregulation

animals control solute concentrations in interstitial fluid and balance water fain and loss (homeostasis)

osmoconformers

• do not attempt to control solute/water balance

• internal concentration carries as salinity in water changes

• most can tolerate very narrow range of salinity

• go with the flow

osmoregulators

• control internal concentrations

• can generally tolerate wider range of salinities

• this can be done in a variety of ways such as secreting very little urine or using specialized glands to secrete salts

excretion

rids of nitrogenous metabolites and other waste products

• kidneys, lungs, skin, liver

nitrogenous waste - ammonia

very toxic

• bony fish, aquatic invertebrates, larval amphibians

nitrogenous waste - urea

less toxic

• mammals, adult amphibians, cartilaginous fish (sharks and certain rays)

nitrogenous waste - uric acid

relatively non-toxic

• reptiles, birds, insects, land snails

excretory process

1. filtration

2. reabsorption

3. secretion

4. excretion

filtration - first step of excretory process

excretory tubule connects filtrate from blood

•  tubule returns needed substances to your blood and removes wastes.

Bowman’s capsule: cup-like sac that catches the filtered fluid (filtrate)

reabsorption - second step of excretory process

transport epithelia reclaims valuable substances from filtrate and returns them to body fluids

secretion - third step of excretory process

toxins and excess ions are extracted from body fluids and added to contents of excretory tubule

excretion - last step of excretory process

urine leaves system and body