Human Anatomy Final

Vocabulary

Nervous System

• Dendrite – receives signals and carries them toward the cell body

• Cell body (soma) – contains nucleus; metabolic center of neuron

• Axon – carries impulses away from cell body

• Axon terminal – releases neurotransmitters

• Myelin sheath – insulation around axon that speeds conduction

• Schwann cell – produces myelin in the PNS

• Node of Ranvier – gaps in myelin where impulses jump

• Acetylcholine (ACh) – neurotransmitter used by motor neurons and parasympathetic NS

• Epinephrine – hormone/neurotransmitter released during sympathetic responses

• Action potential – electrical nerve impulse

• Polarized – resting state; inside negative

• Depolarization – Na⁺ enters cell, making inside positive

• Repolarization – K⁺ leaves cell, restoring negative charge

• Afferent neuron – sensory neuron carrying information TO CNS

• Efferent neuron – motor neuron carrying information FROM CNS

• Interneuron – neuron within CNS connecting sensory and motor neurons

• Reflex arc – pathway producing automatic response

Endocrine

• Tropic hormones – hormones that stimulate other endocrine glands

Blood/Circulation

• Plasma – liquid portion of blood

• Formed elements – RBCs, WBCs, platelets

• Erythrocytes – red blood cells

• Leukocytes – white blood cells

• Platelets – clotting cell fragments

• Megakaryocytes – bone marrow cells that produce platelets

• Hematocrit – % of blood volume occupied by RBCs

• Hemostasis – stopping blood loss

• Hematopoiesis – blood cell formation

• Coagulation – clot formation

• Agglutination – clumping of RBCs

• Hemolysis – rupture/destruction of RBCs

Cardiovascular

• Arteries – carry blood away from heart

• Veins – carry blood toward heart

• Capillaries – exchange vessels

• Arterioles – small arteries

• Venules – small veins

• Vena cavae – return blood to right atrium

• Aorta – largest artery leaving left ventricle

• Heart rate (HR) – beats/minute

• Stroke volume (SV) – blood pumped per beat

• Cardiac output (CO) = HR × SV

• Peripheral resistance – opposition to blood flow

• Blood pressure – force exerted by blood on vessel walls

• Systole – contraction

• Diastole – relaxation

Fetal Circulation

• Foramen ovale – bypasses lungs (RA → LA)

• Ductus arteriosus – bypasses lungs (pulmonary trunk → aorta)

• Ductus venosus – bypasses liver

Immunity

• Lymph – fluid in lymphatic vessels

• Antigen – substance that triggers immune response

• Antibody – protein that binds antigen

• Pyrogen – fever-causing substance

• Interferon – antiviral protein

• Chemotaxis – movement toward chemicals

• Membrane attack complexes (MACs) – complement proteins that punch holes in pathogens

• Antigen-presenting cells (APCs) – display antigens to activate T cells

Respiratory

• Oral cavity – mouth

• Nasal cavity – filters, warms, humidifies air

• Pharynx – throat

• Larynx – voice box

• Epiglottis – prevents food entering airway

• Trachea – windpipe

• Bronchus – airway entering lungs

• Alveoli – gas exchange sacs

• Surfactant – prevents alveolar collapse

Chapter 7 – Nervous System

CNS vs PNS

Central Nervous System (CNS)

• Brain

• Spinal cord

Peripheral Nervous System (PNS)

• Cranial nerves

• Spinal nerves

• Ganglia

Somatic vs Autonomic

Divisions of Autonomic NS

Sympathetic ("Fight or Flight")

• Increases heart rate

• Dilates pupils

• Dilates bronchi

• Inhibits digestion

• Increases blood pressure

• Releases epinephrine

Parasympathetic ("Rest and Digest")

• Decreases heart rate

• Constricts pupils

• Stimulates digestion

• Conserves energy

Neuron Parts

Signal pathway:

Dendrites → Cell Body → Axon → Axon Terminals

Reflex Arc (in order)

1. Receptor

2. Sensory neuron

3. Interneuron (if present)

4. Motor neuron

5. Effector

Reflex Types

Two-Neuron Reflex

• Sensory → Motor

• Example: Patellar reflex

Three-Neuron Reflex

• Sensory → Interneuron → Motor

• Example: Withdrawal reflex

Nerve Impulse Sequence

Resting (Polarized)

• Na⁺ outside

• K⁺ inside

• Inside negative

Depolarization

• Na⁺ channels open

• Na⁺ enters

Repolarization

• K⁺ channels open

• K⁺ leaves

Sodium-Potassium Pump

• Pumps 3 Na⁺ out

• Pumps 2 K⁺ in

• Restores resting conditions

Chapter 9 – Endocrine System

Major Endocrine Glands

Three Stimuli for Hormone Release

Hormonal

Hormone stimulates hormone release

Example:

• TSH → Thyroid

Humoral

Blood levels trigger release

Example:

• Low blood calcium → PTH

Neural

Nerve stimulation triggers release

Example:

• Sympathetic stimulation → Adrenal medulla

Chapter 10 – Blood

Blood Type Compatibility

Universal Donor

• O⁻

Universal Recipient

• AB⁺

Rh Factor

Rh+

• Has Rh antigen

Rh-

• No Rh antigen

Rh− should not receive Rh+ blood.

Why Hemolysis Occurs

Antibodies attack incompatible RBC antigens causing:

• Agglutination

• Hemolysis

Blood Cell Abundance

Most → Least

1. Erythrocytes

2. Platelets

3. Leukocytes

Granulocytes

• Neutrophils

• Eosinophils

• Basophils

Agranulocytes

• Lymphocytes

• Monocytes

Hemostasis (3 Steps)

1. Vascular Spasm

Damaged vessel constricts

2. Platelet Plug

Platelets stick together

3. Coagulation

Fibrin clot forms

Approximate clotting time:

• 3–6 minutes

Centrifuged Blood

Top:

• Plasma (~55%)

Middle:

• Buffy coat

  • WBCs

  • Platelets

Bottom:

• RBCs (hematocrit)

Chapter 11 – Cardiovascular System

Blood Flow Through Heart

Vena Cava
→ Right Atrium
→ Tricuspid Valve
→ Right Ventricle
→ Pulmonary Semilunar Valve
→ Pulmonary Arteries
→ Lungs
→ Pulmonary Veins
→ Left Atrium
→ Mitral (Bicuspid) Valve
→ Left Ventricle
→ Aortic Semilunar Valve
→ Aorta

Ventricular Systole

• Ventricles contract

• Blood ejected

Ventricular Diastole

• Ventricles relax

• Fill with blood

Blood Pressure

Systolic

Pressure during ventricular contraction

Diastolic

Pressure during ventricular relaxation

Example:
120/80

Pulmonary vs Systemic

Pulmonary

Heart ↔ Lungs

Systemic

Heart ↔ Body

Intrinsic Conduction System

SA Node
→ AV Node
→ Bundle of His
→ Bundle Branches
→ Purkinje Fibers

Node Locations

SA Node

Right atrium

AV Node

Lower right atrium

Bundle of His

Upper interventricular septum

AV Valves

Open

During ventricular filling

Closed

During ventricular contraction

Veins vs Arteries

Vessel Pressure

Highest:

• Aorta

Lowest:

• Vena cavae

Exchange:

• Capillaries

Resistance:

• Arterioles

Heart Sounds

Lub (1st)

AV valves close

Dub (2nd)

Semilunar valves close

Fetal Shunts

Chapter 12 – Lymphatic/Immune System

Lymphatic Organs

Lymph Nodes

Filter lymph

Spleen

Filters blood

Thymus

T-cell maturation

Tonsils

Trap pathogens

APC Function

Present antigen to helper T cells.

Examples:

• Macrophages

• Dendritic cells

B Cells

• Mature in bone marrow

• Produce antibodies

• Humoral immunity

T Cells

• Mature in thymus

• Cell-mediated immunity

Types:

• Helper T

• Cytotoxic T

• Regulatory T

Fever

Benefits:

• Slows pathogen growth

• Enhances immune response

Humoral Immunity

Cells:

• B cells

• Plasma cells

Action:

• Antibody production

Cell-Mediated Immunity

Cells:

• T cells

Action:

• Destroy infected cells

Defense Lines

First Line

Physical barriers

• Skin

• Mucus

Second Line

Innate defenses

• Fever

• Inflammation

• Interferons

• Phagocytes

• Complement

Third Line

Adaptive immunity

• B cells

• T cells

Types of Immunity

Natural Active

Get disease and recover

Artificial Active

Vaccination

Natural Passive

Mother → baby (placenta/breast milk)

Artificial Passive

Antibody injection

Chapter 13 – Respiratory System

Air Pathway

Nasal/Oral Cavity
→ Pharynx
→ Larynx
→ Trachea
→ Bronchi
→ Bronchioles
→ Alveoli

Functions

Nasal Cavity

• Filters

• Warms

• Humidifies

Larynx

• Voice production

Trachea

• Conducts air

Bronchi

• Carry air to lungs

Alveoli

• Gas exchange

Stimuli Increasing Respiration Rate

• Increased CO₂

• Decreased blood pH

• Low O₂ (less important)

• Exercise

Gas Exchange

Occurs at:

• Alveoli and pulmonary capillaries

Mechanism:

• Simple diffusion

Oxygen

Alveoli → Blood

Carbon Dioxide

Blood → Alveoli

Role of Mucus

• Traps dust

• Traps microbes

• Protects respiratory tissues

High-Yield Questions Frequently Asked on Exams

1. Fight or flight = Sympathetic

2. Rest and digest = Parasympathetic

3. Afferent = Toward CNS

4. Efferent = Away from CNS

5. Universal donor = O−

6. Universal recipient = AB+

7. Lub = AV valves close

8. Dub = Semilunar valves close

9. SA node = pacemaker

10. Gas exchange occurs in alveoli

11. Humoral immunity = B cells

12. Cell-mediated immunity = T cells

13. Foramen ovale and ductus arteriosus bypass lungs

14. Ductus venosus bypasses liver

15. Cardiac Output = Heart Rate × Stroke Volume