bio 102 3

parts of an animals body plan

symmetry and body plan, bioenergetics and thermoregulation, and tissues

bioenergetics

the branch of biochemistry that focuses on how cells transform energy, often by producing, storing or consuming adenosine triphosphate (ATP)

two types of symmetry

radial & bilateral

diffusion

how small unicellular organisms get nutrients (exchange/movement from high → low solution levels)

what is cell size constrained by?

surface area to volume ratio

as the cell gets larger…

the surface area to volume ratio decreases

how do larger organism’s cells change?

they have more cells, not bigger cells

what is possible with such a high number of cells?

specialization

what limits body size?

necessity to get nutrients to reach the whole body, gravity on land, drag in water, skeleton weight, and surface area to volume ratio (in supporting skeletons and heat dissipation)

basal metabolic rate

average amount of energy used by an organism in a non-active state

excess energy is given off as heat

energy from nutrients is used in animal body to fuel anabolic reactions

endotherms

maintain a relatively constant body temperature

surface area to volume ratio

surface area increases geometrically, volume increases exponentially. the number of cells increases to make the surface area larger and makes the volume increase less aggressively or not at all, so the SA-V ratio is higher

ectotherms

use the surrounding environment to regulate their body temperature

lack insulation which increases their dependence on the environment for body heat

metabolic rate

amount of energy expended by an animal over a specific time

small vs large endotherms and basal metabolic rate

heat goes through skin, therefore since larger animals have more skin to be released they hold their heat in better. smaller animals have a higher BMR because they can’t hold heat as well, therefore dedicate more energy to it.

do ectotherms have a higher or lower BMR than endotherms?

lower because they don’t need to expend energy to maintain their body temperature

do active animals have a higher BMR or inactive ones?

higher animals

two types of tissues

parazoa and eumetozoa

parazoa

lack defined tissues and organs, can disaggregate and aggregate their cells

eumetozoa

have distinct and well-defined tissues, have irreversible differentiation for most cell types

• have unique tissues, absent in fungi and plants, which allow coordination (nerve tissue) or motility (muscle tissue)

4 main types of animal tissues

epithelia, connective tissues, muscles, and neurons

epithelia

line cavities, open spaces, and surfaces

what do connective tissues do?

connect tissues together, provide support

muscles

generate movement

neurons

generate and send electrical signals

what are epithelial tissue classified by?

number of layers and the shape of the cell

epithelial tissues role

cover the outside of organs and structures in the body and line the lumens of organs in a single layer or multiple layers of cells

simple epithelia

single layer of cells

stratified epithelia

multiple layers of cells

squamos

flat, irregular, round shape

cubodial

cube shaped, central nucleus

columnar

tall, narrow, nucleus toward the base.

transitional

round, simple but appear stratified

connective tissues

made of a matrix consisting of living cells and a non living substance

ground substance

usually contains some combination of collagen, elastic, or reticular fibers

non living substance making up the connective tissue is also called the ground substance

muscle tissues types

skeletal, smooth, and cardiac

skeletal

voluntary, striated

smooth

involuntary, no striations

cardiac

involuntary, striated, intercalated discs

striated

multiple layers

nervous tissue

consists of neurons and neuroglia, generates and transmits electrical impulses

neuroglia

supports neurons to let them do their job

cell body of neuron

large structure with a central nucleus

projections from the cell body

either dendrites specialized in receiving input or a single axon specialized in transmitting impulses

glial cells

a type of cell that provides physical and chemical support to neurons and maintain their environment

astrocytes

regulate the chemical environment of the nerve cell

oligodendrocytes

insulate the axon so the electrical nerve impulse is transferred more efficiently

homeostasis

aims to keep the internal conditions around a set point (constant and optimal)

if the conditions stray too far from that point homeostatic mechanisms kick in

alteration

the set point of homeostasis changing but it will still work towards a new set point

acclimatization

changes in one organ system to maintain a set point in another organ system (altitude or temperature as an example)

responses to stimulus

positive or negative feedback loop

positive feedback loop

maintains and potentially strengthens the response to stimulus, rare (blood clotting and child birth)

childbirth and positive feedback loop

baby pushed against the cervix which causes it to stretch → stretching of cervix causes nerve impulses to be sent to the brain → the brain stimulates the pituitary to release oxytocin → oxytocin causes the uterus to contract

negative feedback loop

counteracts any internal changes (reverses the direction of the change)

(temperature, glucose, pH, blood calcium)

glucose level and negative feedback loop

blood glucose level rises → pancreas releases insulin → target cells take up glucose & the liver converts glucose to glycogen → blood glucose level falls → the pancreas releases glucagon → liver breaks down glycogen and releases glucose into the blood → blood glucose level rises

neural control of thermoregulation

negative feedback loop

body temperature increases → sweat → evaporation takes up heat & lowers temperature

body temperature decreases → shivering → muscles contracts to generate heat

thermoregulations + examples

controlled by the hypothalamus, must maintain a relatively constant internal temperature to keep enzymes efficient and avoid denaturation

(radiation, convection, conduction, and evaporation)

denaturation

proteins are optimized in a particular environment (temperature). if the protein is not in the right environment it unravels and is no longer 3D.

radiation

radioactive particles from the sun or things like uranium,/plutonium which would kill you

convection

use of air for regulation

conduction

transfer of temperature through direct touch

evaporation

sweat, water evaporates from skin leeching heat from body

3 different diets

herbivores, carnivores, and omnivores

two types of carnivores

obligate and facultative

obligate

those that rely entirely on animal flesh to obtain their nutrients

facultative

those that also eat non animal food in addition to animal food, but generally do best eating animals

incomplete

gastrovascular opening

single opening, food enters and waste exits through mouth and muscular pharynx, lack specialized parts

ex: planarian

complete

alimentary canal

two openings, food enters through the mouth and water exits through the anus

ex: earthworm

invertebrate digestive system

either complete or incomplete gastric system

monogastric digestive system

in the rabbit

the small intestine and cecum are enlarged to allow more time to digest the plant material

rabbits digest their food twice, eat their feces to redigest

avian digestive system

birds

don’t have teeth so their stomach has two chambers

esophagus has a pouch

has one opening to excrete urine and feces

avian stomach chambers

proventriculus and gizzard

proventriculus

where gastic juices are produced to digest the food before it enters the stomach

gizzard

where the food is stored, soaked, and mechanically ground

avian esophagus pouch

crop

crop

stores food

ruminants digestive system

four stomachs

stomach one and two both contain prokaryotes and protists to digest cellulose fiber → cud is regurgitated and chewed and swallowed in the third stomach to absorb water → cud passes the fourth stomach where enzymes break cud down

4 ruminant stomachs in order

the rumen, the reticulum, the omasum and the abomasum

dental dietary adaptations

herbivores have incisors for clipping and premolars and molars for grinding, carnivores have sharp incisors & enlarged canines to tear off small pieces of meat, omnivores have a variety

human digestive tract

• complete (alimentary canal)

• part of a tube within a tube body plan

• begins with the mouth and ends in an anus

• digestion is extracellular

extracellular meaning

enzymes break down food but this never goes through the cells, digestive enzymes are secreted by the wall of the digestive tract or by nearby glands

beginnings of human digestion

1.) oral cavity where food is masticated by teeth and moistened by saliva secreted from the…

2.) salivary glands. amylase and lipase in the saliva begin to digest starches and fats

mouth

salivary amylase initiates starch digestion → the tongue mixes chewed food with saliva → mixture is turned into bolus

what is the tongue composed of?

striated muscle

pharynx

where the digestive and respiratory passages come together

• soft palate closes off the nasopharynx

• contains the epiglottis

epiglottis

covers opening into trachea, keeps food from air passages most of the time

human esophagus

takes food into the stomach by peristalsis

peristalsis

rhythmical contractions to move contents in tubular organs

human stomach

acidic and digests most of the protein from food

has deep folds that disappear as the stomach fills to an approximate value of one liter

epithelial lining has millions of gastric pits which drain gastric glands

human small intestine

where further digestion and absorption takes place

also segmentation occurs & nutrients & water to blood vessels and vessels

accessory organs + examples

add secretions (enzymes) that catabolize food into nutrients

salivary glands, liver, pancreas, and gallblader

liver

what does it synthesize/process?

produces bile

process the vitamins and fats and synthesize many plasma proteins

bile

digestive juice that is required for the breakdown of fatty components of the food in the duodenum

pancreas

what does it help digest?

makes juices that neutralize the acidic chyme and contain enzymes need to digest protein and carbs

gallbladder

aids the liver by storing bile and concentrated bile salts

chyme

food mixing with gastric juices

• junction between the stomach and small intestine controlled by a sphincter

• when the sphincter relaxes a small quantity of chyme passes into the small intestine

steps of digestive (mechanical and chemical digestion of food)

pharynx → esophagus → stomach → small intestine → large intestine → feces → anus → defecation

parts of the small intestine

has ridges and furrows that give it a corrugated surface, ville + microvilli

villi

ridges on the surface which contains even smaller ridges (microvilli)