Bio Anatomy Review

What are the main divisions of the nervous system?

* The CNS (Central Nervous System)
* The PNS (Peripheral Nervous System)

Central Nervous System

* brain and spinal cord

Peripheral Nervous System

* includes cranial and spinal nerves extending from the CNS
* sensory nerves
* get information from the senses and transmit them from the brain
* motor nerves
* send information from CNS to muscles
* Voluntary/somatic nerves
* control skeletal muscles by cerebrum
* Involuntary/autonomic
* control of automated functions
* parasympathetic - non-emergency control system
* sympathetic - flight or flight response

Structures that protect the CNS

* Cranium and vertebrae
* protect brain and spinal cord
* Meninges
* three layers of connective tissue around the CNS
* Dura Meiter (outermost layer, tough)
* Arachnoid Mater (middle layer, weblike, full of fluid)
* Pia Mater (innermost layer, soft)
* cerebrospinal fluid
* surrounds brain
* cushions the CNS

Structure of a nerve cell/neuron

3 Parts

* Dendrites
* on the ends
* up to 200 per neuron
* conduct impulses to cell bodies
* recieve information from lots of other neurons
* Cell body
* controls the neuron
* supplies nutrients
* *only in the CNS, as in the PNS they are not an enlarged area*
* Axon
* usually 1 neuron
* connects to \~1,000 dendrites on other neurons

Parts in order that an impulse travels in a neuron

* travel one way
* dendrites → cell bodies →axons
* DCA (reverse alphabetical order)

What is the difference between a neuron and a nerve?

a neuron is part of a nerve

* a nerve is a bundle of neurons

How does an impulse travel from one neuron’s axon to the dendrite of another neuron?

1. threshold stimulus is passed


1. stimulates sodium ions to rush into adjacent areas of the membrane
2. Neuron releases sodium and potassium ions


1. restores resting potential
3. Vesicles of neurotransmitters attached to the cell membrane release and neurotransmitters float across the gap (synapse)
4. Neurotransmitters land on receptors in the dendrite


1. cause them to react, starts a new impulse

What is the space between neurons called?

* Synapse
* synaptic gap
* synaptic cleft

What is the purpose of the myelin sheath?

* insulates neurons in short sections

Where in the nervous system are myelin sheaths found?

* parts of the brain
* throughout the body

What color are myelinated neurons?

* white

What color are unmylinated neurons?

* Grey

How fast do neural impulses travel?

3-300 meters a second

Why is the speed of neural impulses different?

* based on length

Cerebrum

* memory, logic, thought
* 2 hemispheres
* Left hemisphere - language, math, logic
* Right hemisphere - art, music, creativity

Limbic System

* puts an emothional tag on information

Corpus Collosum

* connects the cerebral hemisphere

Thalamus

* relay center for sensory nerves

Hypothalamus

* links CNS and endocrine system
* controls pituary gland

Cerebellum

* motor skills
* balance
* posture
* equillibrium

Pons

* bridge for nerves to cross from right to left cerebellum
* cross between cerebellum and cerebrum

Reticular Activating System (RAS)

filters out unneeded information

* signals cerebrum to wake up

Medulla Oblongata

* handles homeostasis
* bridge of nerves connecting **Rt. Brain → Lft. Body**

and **Lft. Brain → Rt. Body**

What is the function of the frontal lobe?

* motor control
* memory
* thought

What is the function of the Parietal Lobe?

* sensory input from body
* skin, muscles

What is the function of the Temporal Lobe?

* sensory input/interpretation of taste, smell, hearing
* auditory speech

What is the function of the occipital lobe?

* sensory input from eyes
* visual interpretation
* visual speech

What are the 4 steps of learning and memories?

1. RAS filters


1. allows important information in
2. Limbic System


1. puts an emotional tag on information
3. Short-term memory in cerebrem


1. repeats incircular circuits
2. only holds 7-10 bits of information
3. needs repetition/strong input to keep memory alive
4. Long-term memory in cerebrum


1. permanent changes in the synapses caused by continued use of that pathway

Three ways to improve chances of information getting into long term memory

1. repeat and review information
2. Use all your senses
3. Attach already memorized information to the new information

What is a memory? How is it stored?

**Long term memory**

* stored in the brain by causing permanent changes in synapse
* created through continued use of pathway
* lost if not used reinforced in a few weeks

**Short-term Memories**

* repeat in circular circuits

How is a memory accessed?

* synapses in the brain
* connect to any point of the web

How has the vertebrate brain changed over time?

* cerebrum has gotten bigger
* cerebral hemispheres control memory, logic, thought
* more ability for logic and reason

Why does chunking help with memory?

It breaks the memory into smaller parts that are easier to remember.

Why does information get in memory more easily than a list?

* more engaging
* creates more connections/links synapses

Chemoreceptor

* respong to chemical concentrations
* mouth, nose, aorta, carotid artery

Mechanoreceptors

* stimulated by pressure
* skin, cochlea of inner ear, aorta, carotid artery

Proprioreceptors

* awareness of body positions
* muscles, joints, tendons, lingaments

Thermoreceptors

* respond to changes in temperature
* hypothalamus, skin, mucous membranes

Pain Receptors

* respond to chemicals released by damaged cells
* skin, all internal organs except brain

Photoreceptors

* respond to light
* retina

Sensory threshold

* minimum input needed to initiate a response
* if under threshold, no impulse will be sent

What causes the blind spot in each eye?

Where the optical nerve connects to retina

How does the body compensate for the blind spot?

* merges images from each eye into one image

Rods vs. Cones

**Rods**

* low stimulus threshold
* good for low light
* black and white

**Cones**

* high stimulus threshold
* used for color vision
* sharpness

When are people colorblind?

* missing pigments that absorb certain wavelengths

Difference between: Peripheral vison, macula, fovea centralis

**Peripheral Vision**

* see objects with mostly rods
* reflected into macula

**Fovea Centralis**

* cones only
* lightly packed w/sharp focus

**Macula**

* best vision
* rods and cones

Why does smell help you remember things more easily?

* olfactory bulbs are connected directly to the cerebrum, byspassing the RAS, thalamus, and limbic system

What is a reflex?

* instant protection for a small body part

Reflex arc

**Reflex**


1. pain receptors threshold is stimulates
2. sends message to spinal cord
3. interneuron carries impulse to muscles
4. muscles contract and move body part away

**Response**

* sensory nerve to brain gets message
* thalamus notes pain
* brain understands what happened

Structures involved in a reflex arc

1. sensory organ
2. sensory nerve
3. interneuron
4. spinal cord
5. motor nerve → muscles
6. sensory nerve → brain
7. thalamus
8. cerebrum

How does hearing work?

Soundwaves


1. auricle collects soundwaves
2. auditory canal conducts soundwaves to middle ear
3. tympanic membrane (eardrum) bends in response to soundwaves, transferring motion to the ossicles
4. ossicles flex to inner ear fluid

How does equilibrium work?

Space, orientation, balance

* semicircular canals (3 in each ear) contain fluid
* oriented in 3 different planes
* hair cells pick up movement of fluid and pressure of otoliths
* hair cells are attached to receptors which are attached to nerves
* nerves carry to cerebrum

Osmosis

diffusion of water across a semipermeable membrane

* kidneys putting water from blood into urine

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Plasmolysis

loss of water due to osmosis

* diffusion of water out of a cell

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Dialysis

diffusion of dissolved molecules through a semipermeable membrane (large molecules usually cannot diffuse through membranes)

* nutrients from blood entering cells

How does surface area affect diffusion?

Increased surface area → Increased diffusion

How does temperature affect diffusion?

Increased temperature → Increased diffusion (KMT)

How does distance through which molecules must diffuse affect diffusion?

Increased distance → Decreased diffusion

In what form are carbohydrates absorbed into blood?

Simple sugars

* glucose

In what form are fats absorbed into blood?

* Glycerol
* fatty acids

In what form are proteins absorbed into blood?

Neutral Fats (triglycerides)

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Absorbed as fatty acids and glycerol through wall of intestine but absorbed as neutral fats into blood

What is digestion?

The breakdown of large molecules to small molecules to they can enter the blood (absorption) and then enter cells and be used (assimilation).

Vessles of the heart blood travels through, in order

1. Vena cava (superior and inferior)
2. RIght Atrium
3. Right AV Valve (tricuspid)
4. Right ventricles
5. pulmonary semilunar valve
6. right/left pulmonary artery
7. pulmonary artery
8. lungs
9. left pulmonary veins
10. left atrium
11. left AV valve (bicuspid, mitrol)
12. left ventricle
13. aortic semilunar valve
14. descending/ascending aorta

The blood moves through the body collecting CO2 and depositing O2, returns to vena cava

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Anterior portion of digestive system

* controlled by nerves

Posterior portion of digestive system

* controlled by hormones from stomach and small intestine

What are the 4 accessory digestive organism?

* gall bladder
* duodenum
* pancreas
* spleen

What are the 8 functions of the circulatory system?

1. Transports O2 & CO2 from cells
2. transport nutrients to and waste from cells
3. transportation of hormones
4. regulation of body temperature
5. regulate body and blood pH
6. regulation of body water
7. protection against disease (mircobes, toxins, etc.)
8. Protection against loss of body fluids (clotting)

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Artery

* carries **oxygenated** blood
* 1st carrier
* AWAY from heart

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Physical Appearance

* thick walled
* small lumen (opening)

Veins

* carries **deoxygenated** blood
* 3rd carrier
* TOWARDS heart

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Physical Appearance

* thin walled, big lumen (opening)

Capillaries

* carries **both** oxygenated and deoxygenated blood
* 2nd carrier

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Heart Cycle (Physical)

1. **Atrial Systole**


1. atria contracts and blood enters venticles
2. **Ventricular Systole**


1. ventricles contract
2. blood enters arteries
3. **Diastole**


1. atria and ventricals both relax and blood enters atria

Hear Cycle (Electrical)

**P-wave**

* atria contracts, blood enters ventricles

**QRS waves**

* AV valves close

**T-wave**

* AV valves open

What 2 other systems control the circulatory system?

**Nervous**

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**Endocrine**

* hormones

What do red blood cells do?

* carry oxygen/CO2

What do white blood cells do?

* fight disease

What do platelets do?

* help blood clot

What is plasma?

* proteins
* dissolve

Why are O2 and CO2 diffused into blood?

* to be carried throughout the body

How do humans breathe?

* air pulled into lungs through air pressure
* intercostal muscles pull ribs up and out
* thoracic cavity pressure decreases
* air is pulled in

reverse happens to breathe out

What are myelin sheaths made of?

* made of myelin
* a protein in the cell membranes of Schwann cells
* Schwann cells myelinate the neurons

Amygdala

* reflexive emotions

Hippocampus

* spatial orientation

What is a memory?

* sequence of neurons
* stored in small pieces
* large memories are webs of neural chains

Baroreceptors

* sense blood pressure in carotid and aorta

Diffusion

* movement of molecules down a concentration gradient from an area of high concentration to an area of low concentration