Animal Forms and Functions- [Digestive System, Nervous System, The Eyes/ The Ears Flashcards Preview

Biology > Animal Forms and Functions- [Digestive System, Nervous System, The Eyes/ The Ears > Flashcards

Flashcards in Animal Forms and Functions- [Digestive System, Nervous System, The Eyes/ The Ears Deck (56):

The Digestive System

*Gastrovascular cavity

The Digestive System is the chemical breakdown of food into smaller molecules.

*INTRACELLULAR - when a lysosome containing digestive enzymes merges with a food vacuole.
*Food is first digested in a GASTROVASCULAR cavity by EXTRA CELLULAR digestion and then absorbed by individual cells.


Digestion in Humans:
Four groups of molecules encountered:What do they break down?
1. Starches -->
2. Proteins -->
3. Fats --->
4. Nucleic acids --->`

1. Starches --> breaks down to glucose
2. Proteins --> breaks down to amino acids
3. Fats ---> breaks down to fatty acids/glycerol
4. Nucleic acids ---> breaks down to nucleotides.


Digestion follows a specific series of events
1. Mouth
*salivary a-amylase-what does it break down?
- *bolus

Salivary a-amylase breaks down (starch --> maltose), chewing creates BOLUS which is swallowed.

BOLUS - is a mass of food that has been chewed up.


Digestion follows a specific series of events
2. Pharnyx(throat)

This is where food and air passages cross; the EPIGLOTTIS, flap of tissue, blocks trachea so only solid and liquid enter...


Digestion follows a specific series of events
3. Esophagus

Helps Food move through the esophagus, a tube leading to the stomach, by muscular contractions called PERISTALSIS.
-PERISTALSIS is the involuntary contraction of smooth muscles. It allows the movement of food thru the digestive tract.


Digestion follows a specific series of events
4. Stomach
*gastric juice
* Exocrine glands

-Storage- how many liters does it store?
- Mixing - CHYME

The stomach secretes GASTRIC JUICE, a mixture of digestive enzymes and hydrochloric acid (HCL),
Stomach contains EXOCRINE GLANDS.

Storage - Accordionlike folds, allows 2-4 liters of storage.
Mixing - The stomach mixes the food w water & gastric juice to produce a creamy medium called CHYME.

CHYME is liquified food. It is first referred as BOLUS before turning into CHYME.


Digestion follows a specific series of events
4. Stomach
*Physical breakdown
* Chemical Breakdown
-pepsin, parietal cells
- Peptic Ulcers
*Controlled Release -pyloric sphincter

Physical Breakdown - muscles break down food, HCL denatures proteins & kills bacteria.

Chemical Breakdown - PEPSIN(secreted by Chief cells) Digests proteins; (pepsinogen activated by HCL, which is secreted by PARIETAL CELLS.

PEPTIC ULCERS = caused by failure of mucosal lining to protect stomach. This causes pain.
- Ulcers can be caused by excess stomach acid.
Controlled Release -Movement of chyme into the small intestine is regulated by a valve at the end of the stomach, the PYLORIC SPHINCTER.


Digestion follows a specific series of events
4. Stomach
Small intestine
*Pyloric SPhincter
Small Intestines enzymes

PYLORIC SPHINCTER acts as a barrier b/w stomach and small intestine.
Food goes from stomach to small intestine through the PYLORIC SPHINCTER - the first 25 cm of the small intestine, the DUODENUM, continues the digestion of starches and proteins as well as remaining food types (fats & nucleotides)

The wall of the samll intestine is the source of various enzymes, including PROTEOLYTIC enzymes (or PROTEASES, enzymes that digest proteins, such as AMINOPEPTIDASE), maltase and lactase9for digestion of saccharides), and PHOSPHATASES.


The Digestive System

-What does it secrete?
-Trypsin, chymotrypsin, lipase, pancreatic amylase

The pancreas produces various enzymes, including TRPSIN and CHYMOTRYPSIN(proteases), LIPASE(digestion of fats), and PANCREATIC AMYLASE (digestion of starch).

The Pancrease secretes bicarbonate.


The Digestive System
- Liver -What does it produce/secretes?

*Gall Bladder

The liver produces bile stored in GALL BLADDER, flows thru bile duct which merges with pancreatic duct.


The Digestive System
-The remainder of the small intestine absorbs the breakdown products of food. IT is characterized by VILLI and MICROVILLI.

Remainder of small intestine (6m) absorbs breakdown products (VILLI and MICROVILLI)


The Digestive System
- Large Intestine(colon)- What does it reabsorbed?
*Rectum ---> Anus
*Symbiont/Vitamin K

- reabsorption of water and salts to form FECES; 1.5m long.
- Feces stored at end of L.I. in the RECTUM ---> excreted thru ANUS.
-Herbivores is a large CECUM(cellulose digestion) with the help of bacteria.
-Bacteria is a SYMBIONT in large intestine = main source of VITAMIN K


The Digestive System
Hormones involved in the digestive process
1. Gastrin

Gastrin - a peptide hormone that stimulates secretion of gastric acid(HCL)


The Digestive System
Hormones involved in the digestive process
2. Secretin

Produced by cells lining DUODENUM when food enters; stimulates pancreas to produce bicarbonate.


The Digestive System
Hormones involved in the digestive process
3. Cholecystokinin(CCK) - what organ is this produced by?
What does it secrete?

Produced by S.I. in response to FATS; stimulates gallbladder to contract & release bile and pancreas to release its enzymes.


The Digestive System
Hormones involved in the digestive process
4. Gastric Inhibitory Peptide

A hormone secreted by cells of the intestinal mucosa that blocks the secretion of HCL into the stomach.


Digestion in plants and fungi
*Intracellular digestion-

Plants have no digestive system.

Intracellular Digestion - store primarily STARCH in seeds, stems, and rootsl when nutrients are required, polymers are broken down (into glucose, fatty acid, glycerol, and amino acids) bu enzymatic HYDROLSIS.


Digestion in plants and fungi
*Extracellular digestion
* Venus Flytrap

- Several plants must obtain nutrient from environment

-Fungi - rhizoids of bread mold, secrete enzymes into bread, producing simple digestive products which are then absorbed by diffusion into rhizoid.

Venus Flytrap - enzymes digest trapped fly ***Still Autotrophic***


The Nervous System
*Cell Body
* Dendrite
* Axon

The basic structural unit of the nervous system is a nerve cell, or NEURON. It
-Has 3 parts: Cell Body, Dendrite, Axon
-Cell Body contains nucleus/other organelles
-Dendrites - Receive information and transfer it TO CELL BODY
-Axon - Transfers AWAY from cell body.


The Nervous System
-Glial Cells

Nervous tissue support cells; capable of cellular division.


The Nervous System


Produce myelin in CNS; wrap many times around axons.


The Nervous System

-Schwann cells(glial cells)
*Myelin sheaths
*Nodes of Ranvier
* Saluatory conduction

Produce myelin in PNS.Myelin sheaths act insulators to speed up the impulse. They are separated by NODES OF RANVIER(gaps between Schwann cell). Instead of traveling continuously down axon, action potential jumps from node to node (SALUTATORY CONDUCTION), speeding up impulse


The Nervous System

- What kind of species have myelinated axons?
- What color do myelinated appear?
- What color are neuronal cell bodies?

- Only vertebrates have myelinated axons.
- Myelinated axons appear white(white matter)
-Neuronal cell bodies are gray (gray Matter)


The Nervous System

Glial cells:
- Microglia
-Satellite cells

- Microglia= Phagocytes(can remove dead/dying neurons) of the CNS
-Ependymal = Use cilia to circulate/move CSF(cerebral spinal fluid)
-Satellite cells = Support ganglia(groups of cell bodies in PNS)
-Astrocytes = Most abundant neuroglia. physical support to neurons of CNS; maintain mineral and nutrient balance.


The Nervous System

3 Types of Neurons:

1. Sensory (Afferent) - give example
2. Motor (Efferent) - example
3. Association(Interneuron)

1. Sensory (Afferent) - are nerve cells that transmit sensory information (sight, sound, feeling, etc.). (EX- neurons in retina of eye)

2. Motor (Efferent) - stimulate effectors, target cells that elicit some response (Ex- neurons may stimulate the muscles, sweat glands, or cells in the stomach to secrete gastrin.
BRAIN----> M

3. Association(Interneuron) - Located in spinal cord & brain - receive impulses from sensory and send impulses to motor neurons. They are INTEGRATORS, as they evaluate impulses for appropriate response
~ 99% of nerves are interneurons.


The Nervous System
- Neurons

Polarized - The membrane of an unstimulated neuron is POLARIZED, although a high concentration of Na+ is present outside the cell and a high concentration of K+ is present inside the cell.

-Additionally, neuron membranes are selectively permeable to K+ as opposed to Na+, which helps to maintain the polarization.


The Nervous System - Neurons

*Resting Potential
-Number of millivolts?

The resting potential describes the unstimulated, polarized state of a neuron (at about -70 mV)


The Nervous System - Neurons

-Action Potential
*Gated ion channels
*Threshold level that is reached

In response to a stimulus, GATED ION CHANNELS in the membrane suddenly open and permit the Na+ into the cell, DEPOLARIZING it. If the THRESHOLD LEVEL is reached (~50 mV), it will cause an ACTION POTENTIAL that will result in opening of (voltage gated) Na+ channels down the entire length of the neuron . ALL OR NOTHING EVENT!!!!


The Nervous System - Neurons

*Whats in and out?

In response to Na+ flow in, more gated ion channels let K+ out of the cell, restoring polarization- but the Na+ are IN and the K+ are OUT


The Nervous System - Neurons


By the time the channels close, too much K+ is released (~80 millivolts)


The Nervous System - Neurons
- Refractory Period

Neuron will NOT respond to new stimulus until Na+/K+ pumps return the ions to their resting potential locations(outside/in respectively) if absolute. The refractory period is what prevents an AP from moving backwards.


The Nervous System - Neurons
-Myelin sheath
*Schwann cells

Some neurons posses a MYELIN SHEATH which consists of a series of SCHWANN CELLS that encircle the axon.


The Nervous System - Neurons
Synapse or synaptic cleft

A SYNAPSE, or SYNAPTIC CLEFT, is the gap that separates adjacent neurons.


The Nervous System - Neurons
-Presynaptic cell to postsynaptic cell

-Gap Junctions

Transmission of an impulse across a synapse, from PRESYNAPTIC CELL TO POSTSYNAPTIC CELL may be electrical or chemical.

GAP JUNCTIONS - In electrical synapses, the action potential travels along the membrane of GAP JUNCTIONS, small tubes of cytoplasm that connect adjacent cells.


The Nervous System
- Transmission across synapse
*1. Electrical
*2. Chemical

Presynaptic cell --> postsynaptic cell

1. Electrical - action potential travels along membranes of gap junctions (less common); fast; cardiac and visceral smooth muscle.

2. Chemical - most typical in animal cells; undirectional(unlike electrical)


The Nervous System
- Transmission across synapse
1. Calcium(Ca2+) gates open.
2. Synaptic vesicles release neurotransmitter
3. Neurotransmitter binds with with postsynaptic
4. Postsynaptic membrane is excited or inhibited.

5. Neurotransmitter is degraded and recycled.

1. Calcium(Ca2+) gates open.- depolarization allows Ca2+ to enter the cell

2. Synaptic vesicles release neurotransmitter- Influx causes release into cleft.

3. Neurotransmitter binds with with postsynaptic - Diffusion and binding.

4. Postsynaptic membrane is excited or inhibited. - 2 possible outcomes:
1)Na+ gates open----> Excitatory postsynaptic potential (EPSP)
2) K+ gates open = INhibitory postsynaptic potential(IPSP)

5.Neurotransmitter is degraded and recycled.- broken down by enzymes in cleft and recycled.


Some common Neurotransmitters

1. Acetycholine
*Neuromuscular Junctions

Commonly secreted at NEUROMUSCULAR JUNCTIONS ---> muscle contraction/relaxation. Inhibitory everywhere else.


Some common Neurotransmitters
2. Epinephrine, norepinephrine, dopamine, and serotonin

Derived from Amino Acids.

- Secretes b/w neurons of CNS
- Sympathetic Nervous System.


The Nervous System
Some common Neurotransmitters
3. Gamma aminobutyric acid (GABA)

Inhibitory neurotransmitter among neurons in the brain.


The Nervous System

What are the 2 parts of the nervous system?

1. Central Nervous System(CNS) - brain & spinal cord.

2. Peripheral Nervous System - consists of sensory neurons that transmits info to the CNS and motor neurons that trasmit impulses from the CNS to effectors.


The Nervous System

What are 2 parts of the PNS?
Which is voluntary/involuntary

1. Somatic Nervous System - directs contraction of skeletal muscles.(VOLUNTARY movement)

2. Autonomic Nervous System - controls the activities of organs and various involuntary muscles, such as cardiac and smooth muscles.(INVOLUNTARY movement)


The Nervous System

What are 2 divisions of the autonomic nervous system?

1. Sympathetic Nervous System - "Flight or Fight"

2. Parasympathetic Nervous System - "Rest or Digest"


The Nervous System

What does a reflex arc? How many neurons?

A rapid, involuntary response to a stimulus involving 2 or 3 neurons, but brain DOES NOT integrate the sensory and motor activities.

Ex- Knee-jerk reflex


The Nervous System
CNS-What does it consist of
-What kinds of matter does it consist of?

CNS consists of the brain and spinal cord.
Brain - outer grey matter (cell bodies) and inner white matter (axons); forebrain, midbrain, hindbrain.


The Nervous System
*Cerebral Cortex
-Olfactory Bulb

Forebrain - Largest & most important brain region. It contains a CEREBRAL CORTEX(processes sensory input/ important for memory and creative thought.

THALAMUS - Relay for spinal cord and cerebral cortex
HYPOTHALAMUS - water balance, blood pressure, and temp regulation, hunger, thirst, sex)


The Nervous System
-Mindbrain- function
- Hindbrain - function
*Cerebellum -function
*Pons - function
*Medulla Oblongata- function

-Mindbrain = Replay center for visual/auditory impulses; motor control.

HINDBRAIN - Posterior part of brain.

CEREBULLUM - Maintenance of balance, hand-eye coord., timing of rapid movements.

PONS - Relay center to allow communication b/w cortex and cerebellum.
MEDULLA OBLONGATA - Breathing, heart rate,)


The Nervous System
- Brainstem- What does it consist of?
- Spinal Cord
- Dorsal Horn
- Ventral Horn

-Brainstem = consists of midbrain + medulla oblongata + pons. Connects the cerebrum w/ the spinal cord.

SPINAL CORD - out white/inner gray(cell bodies)
DORSAL HORN - Sensory info enters here.
VENTRAL HORN - All motor info exits thru the VENTRAL HORN.


The Muscular System

-Muscle Fibers

A skeletal muscle consists of numerous muscle cells are called MUSCLE FIBERS.


The Nervous System- 5 types of sensory receptors.
1. Mechanoreceptors
3. Nociceptors
4. Electromagnetic receptors
5. Chemoreseptors

1. Mechanoreceptors - touch
2.Thermoreceptors - temperature
3. Nociceptors - Pain
4. Electromagnetic receptors - light
5. Chemoreseptors - taste, smell, blood chemistry.


The Eye
-Eye Cornea -> pupil -->lens --> retina

Describe each

-Eye Cornea (focuses light) ----> PUPIL (pigmented) ---> LENS (controlled by cilliary muscles ----> RETINA (light sensitive cells)


The Eye


Cones - color
Rods - no color

Fovea - packed with cones, important for high acuity vision


The Eye
Eye Disorders

- Astigmatism

-MYOPIA = nearsightedness
-HYPEROPIA = farsightedness
- ASTIGMATISM = irregularly shaped cornea
-CATERACTS = lens becomes opaque --> light cant enter
-GLAUCOMA= increase in pressure of eye due to blocking of outflow of aqueous humor.


The Ear
3 parts of the ear

3 main parts : Outer, Middle Ear, Inner ear


The Ear
Outer Ear has which parts?

Outer ear - auricle/pinna and auditory canal
*Direct sound into external auditory canal


The Ear
Middle Ear does what and has what parts

Middle Ear - amplifies sound; tympanic membrane(ear drum) begins the middle ear and vibrates at same frequency as incoming sound ==> ossicles (malleus, incus, and stapes)


The Ear
-Inner Ear
*Semicircular canals

Waves move thru the COCHLEA. Movement is detected by HAIR CELLS.

The inner ear also has SEMICIRCULAR CANALS responsible for balance.