PLTW Biomed U1

Vital Signs

Measurements of the body’s most basic functions to assess health.

heart rate, blood pressure, respiration rate, body temperature

what are some vital signs?

polygraph

Measures physiological responses to questions (heart rate, breathing, skin conductivity).

Locard’s Exchange Principle

Every contact leaves a trace.

When two objects come into contact, material is transferred between them

fingerprints

• Types: Loop, whorl, arch.

• Uses: Identification because patterns are unique to each individual.

• Analysis: Compare ridge endings, bifurcations, and minutiae.

red blood cell, white blood cell, platelets, plasma 

what are the components of blood? 

red blood cells

Carry oxygen using hemoglobin

white blood cell

Fight infection and produce antibodies

platelets

Help blood clotting → when get injury/cut

plasma

liquid part that transport nutrients, hormones, and waste

Presumptive Tes

Suggests blood may be present (e.g., color change, luminol)

Confirmative Test

Confirms blood is human (e.g., Takayama test).

type a

a antigen, b antibody

type b

b antigen, a antibody

type ab

a + b antigen, no antibody (universal reciever)

type o

not antigens, a + b antibody (universal doner)

Agglutination

Clumping indicates reaction between antibody and antigen.

sugar (deoxyribose), phosphate group, nitrogen base 

what are nucleotides made of? 

adenine (a), thymine (t), cytosine (c), guanine (g)

what are the bases of nucleotides?

Purines

Adenine (A) & Guanine (G) → double ring

Pyrimidines

Cytosine (C) & Thymine (T) → single ring

thymine (t)

 which does adenine pair with?

adenine (a)

which does thymine pair with?

guanine (g) 

which does cytosine pair with? 

cytosine (C) 

which does guanine pair with? 

prokaryote 

no nucleus, circular dna, no organelles.

ex: bacteria 

eukaryotic

yes nucleus, linear dna, membrane bound organelles

ex: animal, plants. 

restriction enzyme

cuts dna at specific sequence

gel electrophoresis

separates dna fragments by size; small move faster/at bottom

independent variable

what you change

dependent variable

what changes as a result (effect) → what you’re measuring

control

what you keep the same for comparison

hypothesis 

testable prediction 

hair root, shaft, cuticle, cortex, medulla 

what are the components of hair (outer → inner) 

cuticle

outer protective layer of hair

cortex

part of hair that contain pigment, and provide strength

medulla

inner core of hair, may be fragmented/continuous

grid serach

divide area into squares, systematic coverage

good for large outdoor crime

line/strip search

walk in straight lines, good for large areas

spiral search

circle inward/outward, used for places with no physical barrier like open water or small confine space

begin point of crime scene and go out (outward) , or begin at outside point and go to critical point (inward)

Zone Search

separates scene into different zones, assign zones to teams, combine findings.

good for easily identifiable places like houses/buildings

antigen

A “name tag” on the surface of cells (like red blood cells) that tells your immune system what it is. Each blood type has specific antigens.

antibody 

A “soldier” in your immune system that attacks anything with the wrong antigen/unfamiliar antigen 

ex: if blood is a, they will attack b

link method

forming links between crime scene activity and places → finding assocations

good for large and small indoor outdoor crime scenes 

no patterns

wheel/ray method

starts at critical point and then travel outward in straight lines

good for small circle crime scenes

hair cuticle

part of the hair thats below the surface

shaft

part of the hair that can be seen above the skin

1. anagen 

2. catagen

3. telogen 

growth cycle of hair 

anagen

active hair growth phase

catagen

follicle shrinks → transition phase of hair growth

telogen

hair sheds → resting → dermal papilla separates